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Kostoglou K, Bello-Robles F, Brassard P, Chacon M, Claassen JA, Czosnyka M, Elting JW, Hu K, Labrecque L, Liu J, Marmarelis VZ, Payne SJ, Shin DC, Simpson D, Smirl J, Panerai RB, Mitsis GD. Time-domain methods for quantifying dynamic cerebral blood flow autoregulation: Review and recommendations. A white paper from the Cerebrovascular Research Network (CARNet). J Cereb Blood Flow Metab 2024:271678X241249276. [PMID: 38688529 DOI: 10.1177/0271678x241249276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Cerebral Autoregulation (CA) is an important physiological mechanism stabilizing cerebral blood flow (CBF) in response to changes in cerebral perfusion pressure (CPP). By maintaining an adequate, relatively constant supply of blood flow, CA plays a critical role in brain function. Quantifying CA under different physiological and pathological states is crucial for understanding its implications. This knowledge may serve as a foundation for informed clinical decision-making, particularly in cases where CA may become impaired. The quantification of CA functionality typically involves constructing models that capture the relationship between CPP (or arterial blood pressure) and experimental measures of CBF. Besides describing normal CA function, these models provide a means to detect possible deviations from the latter. In this context, a recent white paper from the Cerebrovascular Research Network focused on Transfer Function Analysis (TFA), which obtains frequency domain estimates of dynamic CA. In the present paper, we consider the use of time-domain techniques as an alternative approach. Due to their increased flexibility, time-domain methods enable the mitigation of measurement/physiological noise and the incorporation of nonlinearities and time variations in CA dynamics. Here, we provide practical recommendations and guidelines to support researchers and clinicians in effectively utilizing these techniques to study CA.
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Affiliation(s)
- Kyriaki Kostoglou
- Department of Electrical and Computer Engineering, McGill University, Montreal, QC, Canada
- Institute of Neural Engineering, Graz University of Technology, Graz, Austria
| | - Felipe Bello-Robles
- Departamento de Ingeniería Informática, Universidad de Santiago de Chile, Santiago, Chile
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université Laval, Quebec, QC, Canada
- Research Center of the Institut universitaire de cardiologie et de pneumologie de Québec, Quebec, QC, Canada
| | - Max Chacon
- Departamento de Ingeniería Informática, Universidad de Santiago de Chile, Santiago, Chile
| | - Jurgen Ahr Claassen
- Department of Geriatrics, Radboud University Medical Center, Research Institute for Medical Innovation and Donders Institute, Nijmegen, The Netherlands
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Marek Czosnyka
- Department of Clinical Neurosciences, Neurosurgery Department, University of Cambridge, Cambridge, UK
| | - Jan-Willem Elting
- Department of Neurology and Clinical Neurophysiology, University Medical Center Groningen, Groningen, The Netherlands
| | - Kun Hu
- Medical Biodynamics Program, Division of Sleep and Circadian Disorders, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
| | - Lawrence Labrecque
- Department of Kinesiology, Faculty of Medicine, Université Laval, Quebec, QC, Canada
- Research Center of the Institut universitaire de cardiologie et de pneumologie de Québec, Quebec, QC, Canada
| | - Jia Liu
- Laboratory for Engineering and Scientific Computing, Institute of Advanced Computing and Digital Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China
| | - Vasilis Z Marmarelis
- Department Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA
| | - Stephen J Payne
- Institute of Applied Mechanics, National Taiwan University, Taipei, Taiwan
| | - Dae Cheol Shin
- Department Biomedical Engineering, Viterbi School of Engineering, University of Southern California, Los Angeles, CA, USA
| | - David Simpson
- Institute of Sound and Vibration Research, University of Southampton, Southampton, UK
| | - Jonathan Smirl
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
- Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Ronney B Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine (CHiASM), Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation, Glenfield Hospital, Leicester, UK
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, QC, Canada
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2
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Torabi M, Mitsis GD, Poline JB. On the variability of dynamic functional connectivity assessment methods. Gigascience 2024; 13:giae009. [PMID: 38587470 PMCID: PMC11000510 DOI: 10.1093/gigascience/giae009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 12/05/2023] [Accepted: 02/15/2024] [Indexed: 04/09/2024] Open
Abstract
BACKGROUND Dynamic functional connectivity (dFC) has become an important measure for understanding brain function and as a potential biomarker. However, various methodologies have been developed for assessing dFC, and it is unclear how the choice of method affects the results. In this work, we aimed to study the results variability of commonly used dFC methods. METHODS We implemented 7 dFC assessment methods in Python and used them to analyze the functional magnetic resonance imaging data of 395 subjects from the Human Connectome Project. We measured the similarity of dFC results yielded by different methods using several metrics to quantify overall, temporal, spatial, and intersubject similarity. RESULTS Our results showed a range of weak to strong similarity between the results of different methods, indicating considerable overall variability. Somewhat surprisingly, the observed variability in dFC estimates was found to be comparable to the expected functional connectivity variation over time, emphasizing the impact of methodological choices on the final results. Our findings revealed 3 distinct groups of methods with significant intergroup variability, each exhibiting distinct assumptions and advantages. CONCLUSIONS Overall, our findings shed light on the impact of dFC assessment analytical flexibility and highlight the need for multianalysis approaches and careful method selection to capture the full range of dFC variation. They also emphasize the importance of distinguishing neural-driven dFC variations from physiological confounds and developing validation frameworks under a known ground truth. To facilitate such investigations, we provide an open-source Python toolbox, PydFC, which facilitates multianalysis dFC assessment, with the goal of enhancing the reliability and interpretability of dFC studies.
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Affiliation(s)
- Mohammad Torabi
- Graduate Program in Biological and Biomedical Engineering, McGill University, Duff Medical Building, 3775 rue University, Montreal H3A 2B4, Canada
- Department of Bioengineering, McGill University, 3480 University Street, Montreal H3A 0E9, Canada
- Neuro Data Science ORIGAMI Laboratory, McConnell Brain Imaging Centre, Faculty of Medicine, McGill University, 3801 University Street, Montreal H3A 2B4, Canada
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, 3480 University Street, Montreal H3A 0E9, Canada
| | - Jean-Baptiste Poline
- Neuro Data Science ORIGAMI Laboratory, McConnell Brain Imaging Centre, Faculty of Medicine, McGill University, 3801 University Street, Montreal H3A 2B4, Canada
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3
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Dimitriou NM, Demirag E, Strati K, Mitsis GD. A calibration and uncertainty quantification analysis of classical, fractional and multiscale logistic models of tumour growth. Comput Methods Programs Biomed 2024; 243:107920. [PMID: 37976612 DOI: 10.1016/j.cmpb.2023.107920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 10/27/2023] [Accepted: 11/05/2023] [Indexed: 11/19/2023]
Abstract
BACKGROUND AND OBJECTIVE The validation of mathematical models of tumour growth is frequently hampered by the lack of sufficient experimental data, resulting in qualitative rather than quantitative studies. Recent approaches to this problem have attempted to extract information about tumour growth by integrating multiscale experimental measurements, such as longitudinal cell counts and gene expression data. In the present study, we investigated the performance of several mathematical models of tumour growth, including classical logistic, fractional and novel multiscale models, in terms of quantifying in-vitro tumour growth in the presence and absence of therapy. We further examined the effect of genes associated with changes in chemosensitivity in cell death rates. METHODS The multiscale expansion of logistic growth models was performed by coupling gene expression profiles to the cell death rates. State-of-the-art Bayesian inference, likelihood maximisation and uncertainty quantification techniques allowed a thorough evaluation of model performance. RESULTS The results suggest that the classical single-cell population model (SCPM) was the best fit for the untreated and low-dose treatment conditions, while the multiscale model with a cell death rate symmetric with the expression profile of OCT4 (Sym-SCPM) yielded the best fit for the high-dose treatment data. Further identifiability analysis showed that the multiscale model was both structurally and practically identifiable under the condition of known OCT4 expression profiles. CONCLUSIONS Overall, the present study demonstrates that model performance can be improved by incorporating multiscale measurements of tumour growth when high-dose treatment is involved.
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Affiliation(s)
| | - Ece Demirag
- Department of Biological Sciences, University of Cyprus, Nicosia, 2109, Cyprus
| | - Katerina Strati
- Department of Biological Sciences, University of Cyprus, Nicosia, 2109, Cyprus
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, H3A 0E9, QC, Canada.
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Yang E, Milisav F, Kopal J, Holmes AJ, Mitsis GD, Misic B, Finn ES, Bzdok D. The default network dominates neural responses to evolving movie stories. Nat Commun 2023; 14:4197. [PMID: 37452058 PMCID: PMC10349102 DOI: 10.1038/s41467-023-39862-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 06/27/2023] [Indexed: 07/18/2023] Open
Abstract
Neuroscientific studies exploring real-world dynamic perception often overlook the influence of continuous changes in narrative content. In our research, we utilize machine learning tools for natural language processing to examine the relationship between movie narratives and neural responses. By analyzing over 50,000 brain images of participants watching Forrest Gump from the studyforrest dataset, we find distinct brain states that capture unique semantic aspects of the unfolding story. The default network, associated with semantic information integration, is the most engaged during movie watching. Furthermore, we identify two mechanisms that underlie how the default network liaises with the amygdala and hippocampus. Our findings demonstrate effective approaches to understanding neural processes in everyday situations and their relation to conscious awareness.
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Affiliation(s)
- Enning Yang
- Department of Biomedical Engineering, TheNeuro-Montreal Neurological Institute (MNI), McConnell Brain Imaging Centre (BIC), McGill University, Montreal, QC, Canada
- Mila-Quebec Artificial Intelligence Institute, Montreal, QC, Canada
| | - Filip Milisav
- Department of Biomedical Engineering, TheNeuro-Montreal Neurological Institute (MNI), McConnell Brain Imaging Centre (BIC), McGill University, Montreal, QC, Canada
| | - Jakub Kopal
- Department of Biomedical Engineering, TheNeuro-Montreal Neurological Institute (MNI), McConnell Brain Imaging Centre (BIC), McGill University, Montreal, QC, Canada
- Mila-Quebec Artificial Intelligence Institute, Montreal, QC, Canada
| | - Avram J Holmes
- Department of Psychology and Psychiatry, Yale University, New Haven, CT, USA
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, QC, Canada
| | - Bratislav Misic
- Department of Biomedical Engineering, TheNeuro-Montreal Neurological Institute (MNI), McConnell Brain Imaging Centre (BIC), McGill University, Montreal, QC, Canada
| | - Emily S Finn
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH, USA
| | - Danilo Bzdok
- Department of Biomedical Engineering, TheNeuro-Montreal Neurological Institute (MNI), McConnell Brain Imaging Centre (BIC), McGill University, Montreal, QC, Canada.
- Mila-Quebec Artificial Intelligence Institute, Montreal, QC, Canada.
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Flores-Torres S, Dimitriou NM, Pardo LA, Kort-Mascort J, Pal S, Peza-Chavez O, Kuasne H, Berube J, Bertos N, Park M, Mitsis GD, Ferri L, Sangwan V, Kinsella JM. Bioprinted Multicomponent Hydrogel Co-culture Tumor-Immune Model for Assessing and Simulating Tumor-Infiltrated Lymphocyte Migration and Functional Activation. ACS Appl Mater Interfaces 2023. [PMID: 37404007 DOI: 10.1021/acsami.3c02995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 07/06/2023]
Abstract
The immune response against a tumor is characterized by the interplay among components of the immune system and neoplastic cells. Here, we bioprinted a model with two distinct regions containing gastric cancer patient-derived organoids (PDOs) and tumor-infiltrated lymphocytes (TILs). The initial cellular distribution allows for the longitudinal study of TIL migratory patterns concurrently with multiplexed cytokine analysis. The chemical properties of the bioink were designed to present physical barriers that immune T-cells must breech during infiltration and migration toward a tumor with the use of an alginate, gelatin, and basal membrane mix. TIL activity, degranulation, and regulation of proteolytic activity reveal insights into the time-dependent biochemical dynamics. Regulation of the sFas and sFas-ligand present on PDOs and TILs, respectively, and the perforin and granzyme longitudinal secretion confirms TIL activation when encountering PDO formations. TIL migratory profiles were used to create a deterministic reaction-advection diffusion model. The simulation provides insights that decouple passive from active cell migration mechanisms. The mechanisms used by TILs and other adoptive cell therapeutics as they infiltrate the tumor barrier are poorly understood. This study presents a pre-screening strategy for immune cells where motility and activation across ECM environments are crucial indicators of cellular fitness.
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Affiliation(s)
| | - Nikolaos M Dimitriou
- Department of Bioengineering, McGill University, Montreal H3A 0G4, Quebec, Canada
| | - Lucas Antonio Pardo
- Department of Bioengineering, McGill University, Montreal H3A 0G4, Quebec, Canada
| | | | - Sanjima Pal
- Department of Surgery, McGill University, Montreal H3A 0G4, Quebec, Canada
| | - Omar Peza-Chavez
- Department of Bioengineering, McGill University, Montreal H3A 0G4, Quebec, Canada
| | - Hellen Kuasne
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal H3A 0G4, Quebec, Canada
| | - Julie Berube
- Department of Surgery, McGill University, Montreal H3A 0G4, Quebec, Canada
| | - Nicholas Bertos
- Research Institute of the McGill University Health Centre (RI-MUHC), Montreal H3G 2M1, Quebec, Canada
| | - Morag Park
- Department of Biochemistry, McGill University, Montreal H3A 0G4, Quebec, Canada
- Department of Medicine, McGill University, Montreal H3A 0G4, Quebec, Canada
- Department of Oncology, McGill University, Montreal H3A 0G4, Quebec, Canada
- Department of Pathology, McGill University, Montreal H3A 0G4, Quebec, Canada
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal H3A 0G4, Quebec, Canada
| | - Lorenzo Ferri
- Department of Surgery, McGill University, Montreal H3A 0G4, Quebec, Canada
- Research Institute of the McGill University Health Centre (RI-MUHC), Montreal H3G 2M1, Quebec, Canada
| | - Veena Sangwan
- Rosalind and Morris Goodman Cancer Institute, McGill University, Montreal H3A 0G4, Quebec, Canada
| | - Joseph M Kinsella
- Department of Bioengineering, McGill University, Montreal H3A 0G4, Quebec, Canada
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Dagenais R, Mitsis GD. Non-invasive estimation of arterial blood pressure fluctuations using a peripheral photoplethysmograph inside the MRI scanner. Annu Int Conf IEEE Eng Med Biol Soc 2023; 2023:1-4. [PMID: 38083179 DOI: 10.1109/embc40787.2023.10340020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
The blood-oxygen-level-dependent (BOLD) signal measured by functional magnetic resonance imaging (fMRI) is modulated by neural activity through the neurovascular coupling effect, as well as non-neural factors of physiological origin such as heart rate, respiration, and arterial blood pressure (ABP). While the former two effects have been previously characterized, the modulation of the BOLD signal by ABP fluctuations is still poorly understood. This is largely due to the difficulty of obtaining reliable ABP measurements in the MRI environment. Here, we propose a combined experimental and mathematical modeling framework to estimate ABP fluctuations inside the MRI scanner using photoplethysmography (PPG). Specifically, we used concurrent PPG and ABP measurements obtained outside the scanner to train the mathematical model and applied it to PPG measurements obtained inside the MRI scanner. Our results suggest good agreement between the model-predicted and experimentally measured ABP fluctuations and region specific correlations with the BOLD fluctuations.
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7
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Yan X, Boudrias MH, Mitsis GD. Investigation of Methodologies for Extracting Individual Brain Oscillations: Comparisons & Insights. Annu Int Conf IEEE Eng Med Biol Soc 2023; 2023:1-4. [PMID: 38083732 DOI: 10.1109/embc40787.2023.10340684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
There is increasing evidence that the effects of non-invasive brain stimulation can be maximized when the applied intervention matches internal brain oscillations. Extracting individual brain oscillations is thus a necessary step for implementing personalized brain stimulation. In this context, different methods have been proposed for obtaining subject-specific spectral peaks from electrophysiological recordings. However, comparing the results obtained using different approaches is still lacking. Therefore, in the present work, we examined the following methodologies in terms of obtaining individual motor-related EEG spectral peaks: fast Fourier Transform analysis, power spectrum density analysis, wavelet analysis, and a principal component based time-frequency analysis. We used EEG data obtained when performing two different motor tasks - a hand grip task and a hand opening- and-closing task. Our results showed that both the motor task type and the specific method for performing the analysis had considerable impact on the extraction of subject-specific oscillation spectral peaks.Clinical Relevance-This exploratory study provides insights into the potential effects of using different methods to extract individual brain oscillations, which is important for designing personalized brain-machine-interfaces.
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8
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O'Connor D, Chang C, Mitsis GD. Editorial: Advancing the measurement, interpretation, and validation of dynamic functional connectivity. Front Hum Neurosci 2023; 17:1206098. [PMID: 37250698 PMCID: PMC10219630 DOI: 10.3389/fnhum.2023.1206098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 04/24/2023] [Indexed: 05/31/2023] Open
Affiliation(s)
- David O'Connor
- Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Catie Chang
- Departments of Electrical and Computer Engineering, Computer Science, and Biomedical Engineering, Vanderbilt University, Nashville, TN, United States
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9
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Karakis R, Gurkahraman K, Mitsis GD, Boudrias MH. DEEP LEARNING PREDICTION OF MOTOR PERFORMANCE IN STROKE INDIVIDUALS USING NEUROIMAGING DATA. J Biomed Inform 2023; 141:104357. [PMID: 37031755 DOI: 10.1016/j.jbi.2023.104357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 02/24/2023] [Accepted: 04/01/2023] [Indexed: 04/11/2023]
Abstract
The degree of motor impairment and profile of recovery after stroke are difficult to predict for each individual. Measures obtained from clinical assessments, as well as neurophysiological and neuroimaging techniques have been used as potential biomarkers of motor recovery, with limited accuracy up to date. To address this, the present study aimed to develop a deep learning model based on structural brain images obtained from stroke participants and healthy volunteers. The following inputs were used in a multi-channel 3D convolutional neural network (CNN) model: fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity maps obtained from Diffusion Tensor Imaging (DTI) images, white and gray matter intensity values obtained from Magnetic Resonance Imaging, as well as demographic data (e.g., age, gender). Upper limb motor function was classified into "Poor" and "Good" categories. To assess the performance of the DL model, we compared it to more standard machine learning (ML) classifiers including k-nearest neighbor, support vector machines (SVM), Decision Trees, Random Forests, Ada Boosting, and Naïve Bayes, whereby the inputs of these classifiers were the features taken from the fully connected layer of the CNN model. The highest accuracy and area under the curve values were 0.92 and 0.92 for the 3D-CNN and 0.91 and 0.91 for the SVM, respectively. The multi-channel 3D-CNN with residual blocks and SVM supported by DL was more accurate than traditional ML methods to classify upper limb motor impairment in the stroke population. These results suggest that combining volumetric DTI maps and measures of white and gray matter integrity can improve the prediction of the degree of motor impairment after stroke. Identifying the potential of recovery early on after a stroke could promote the allocation of resources to optimize the functional independence of these individuals and their quality of life.
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Affiliation(s)
- Rukiye Karakis
- Department of Software Engineering, Faculty of Technology, Sivas Cumhuriyet University, Turkey
| | - Kali Gurkahraman
- Department of Computer Engineering, Faculty of Engineering, Sivas Cumhuriyet University, Turkey
| | - Georgios D Mitsis
- Department of Bioengineering, Faculty of Engineering, McGill University, Montreal, QC, Canada
| | - Marie-Hélène Boudrias
- School of Physical and Occupational Therapy, Faculty of Medicine and Health Sciences, McGill University, Montreal, QC, Canada; BRAIN Laboratory, Jewish Rehabilitation Hospital, Site of Centre for Interdisciplinary Research of Greater Montreal (CRIR) and CISSS-Laval, QC, Canada.
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10
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Dimitriou NM, Flores-Torres S, Kinsella JM, Mitsis GD. Detection and Spatiotemporal Analysis of In-vitro 3D Migratory Triple-Negative Breast Cancer Cells. Ann Biomed Eng 2023; 51:318-328. [PMID: 35896866 DOI: 10.1007/s10439-022-03022-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Accepted: 07/13/2022] [Indexed: 01/25/2023]
Abstract
The invasion of cancer cells into the surrounding tissues is one of the hallmarks of cancer. However, a precise quantitative understanding of the spatiotemporal patterns of cancer cell migration and invasion still remains elusive. A promising approach to investigate these patterns are 3D cell cultures, which provide more realistic models of cancer growth compared to conventional 2D monolayers. Quantifying the spatial distribution of cells in these 3D cultures yields great promise for understanding the spatiotemporal progression of cancer. In the present study, we present an image processing and segmentation pipeline for the detection of 3D GFP-fluorescent triple-negative breast cancer cell nuclei, and we perform quantitative analysis of the formed spatial patterns and their temporal evolution. The performance of the proposed pipeline was evaluated using experimental 3D cell culture data, and was found to be comparable to manual segmentation, outperforming four alternative automated methods. The spatiotemporal statistical analysis of the detected distributions of nuclei revealed transient, non-random spatial distributions that consisted of clustered patterns across a wide range of neighbourhood distances, as well as dispersion for larger distances. Overall, the implementation of the proposed framework revealed the spatial organization of cellular nuclei with improved accuracy, providing insights into the 3 dimensional inter-cellular organization and its progression through time.
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Affiliation(s)
| | | | | | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, QC, H3A 0E9, Canada
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11
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Panerai RB, Brassard P, Burma JS, Castro P, Claassen JA, van Lieshout JJ, Liu J, Lucas SJ, Minhas JS, Mitsis GD, Nogueira RC, Ogoh S, Payne SJ, Rickards CA, Robertson AD, Rodrigues GD, Smirl JD, Simpson DM. Transfer function analysis of dynamic cerebral autoregulation: A CARNet white paper 2022 update. J Cereb Blood Flow Metab 2023; 43:3-25. [PMID: 35962478 PMCID: PMC9875346 DOI: 10.1177/0271678x221119760] [Citation(s) in RCA: 34] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cerebral autoregulation (CA) refers to the control of cerebral tissue blood flow (CBF) in response to changes in perfusion pressure. Due to the challenges of measuring intracranial pressure, CA is often described as the relationship between mean arterial pressure (MAP) and CBF. Dynamic CA (dCA) can be assessed using multiple techniques, with transfer function analysis (TFA) being the most common. A 2016 white paper by members of an international Cerebrovascular Research Network (CARNet) that is focused on CA strove to improve TFA standardization by way of introducing data acquisition, analysis, and reporting guidelines. Since then, additional evidence has allowed for the improvement and refinement of the original recommendations, as well as for the inclusion of new guidelines to reflect recent advances in the field. This second edition of the white paper contains more robust, evidence-based recommendations, which have been expanded to address current streams of inquiry, including optimizing MAP variability, acquiring CBF estimates from alternative methods, estimating alternative dCA metrics, and incorporating dCA quantification into clinical trials. Implementation of these new and revised recommendations is important to improve the reliability and reproducibility of dCA studies, and to facilitate inter-institutional collaboration and the comparison of results between studies.
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Affiliation(s)
- Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester and NIHR Biomedical Research Centre, Leicester, UK
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, and Research Center of the Institut universitaire de cardiologie et de pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Joel S Burma
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Pedro Castro
- Department of Neurology, Centro Hospitalar Universitário de São João, Faculty of Medicine, University of Porto, Porto, Portugal
| | - Jurgen Ahr Claassen
- Department of Geriatric Medicine and Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Johannes J van Lieshout
- Department of Internal Medicine, Amsterdam, UMC, The Netherlands and Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, UK
| | - Jia Liu
- Institute of Advanced Computing and Digital Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen University Town, Shenzhen, China
| | - Samuel Je Lucas
- School of Sport, Exercise and Rehabilitation Sciences and Centre for Human Brain Health, University of Birmingham, Birmingham, UK
| | - Jatinder S Minhas
- Department of Cardiovascular Sciences, University of Leicester and NIHR Biomedical Research Centre, Leicester, UK
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, Québec, QC, Canada
| | - Ricardo C Nogueira
- Neurology Department, School of Medicine, Hospital das Clinicas, University of São Paulo, São Paulo, Brazil
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Stephen J Payne
- Institute of Applied Mechanics, National Taiwan University, Taipei
| | - Caroline A Rickards
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Andrew D Robertson
- Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, ON, Canada
| | - Gabriel D Rodrigues
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Jonathan D Smirl
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - David M Simpson
- Institute of Sound and Vibration Research, University of Southampton, Southampton, UK
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Shams S, Prokopiou P, Esmaelbeigi A, Mitsis GD, Chen JJ. Modeling the dynamics of cerebrovascular reactivity to carbon dioxide in fMRI under task and resting-state conditions. Neuroimage 2023; 265:119758. [PMID: 36442732 DOI: 10.1016/j.neuroimage.2022.119758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 11/11/2022] [Accepted: 11/18/2022] [Indexed: 11/26/2022] Open
Abstract
Conventionally, cerebrovascular reactivity (CVR) is estimated as the amplitude of the hemodynamic response to vascular stimuli, most commonly carbon dioxide (CO2). While the CVR amplitude has established clinical utility, the temporal characteristics of CVR (dCVR) have been increasingly explored and may yield even more pathology-sensitive parameters. This work is motivated by the current need to evaluate the feasibility of dCVR modeling in various experimental conditions. In this work, we present a comparison of several recently published/utilized model-based deconvolution (response estimation) approaches for estimating the CO2 response function h(t), including maximum a posteriori likelihood (MAP), inverse logit (IL), canonical correlation analysis (CCA), and basis expansion (using Gamma and Laguerre basis sets). To aid the comparison, we devised a novel simulation framework that incorporates a wide range of SNRs, ranging from 10 to -7 dB, representative of both task and resting-state CO2 changes. In addition, we built ground-truth h(t) into our simulation framework, overcoming the conventional limitation that the true h(t) is unknown. Moreover, to best represent realistic noise found in fMRI scans, we extracted noise from in-vivo resting-state scans. Furthermore, we introduce a simple optimization of the CCA method (CCAopt) and compare its performance to these existing methods. Our findings suggest that model-based methods can accurately estimate dCVR even amidst high noise (i.e. resting-state), and in a manner that is largely independent of the underlying model assumptions for each method. We also provide a quantitative basis for making methodological choices, based on the desired dCVR parameters, the estimation accuracy and computation time. The BEL method provided the highest accuracy and robustness, followed by the CCAopt and IL methods. Of the three, the CCAopt method has the lowest computational requirements. These findings lay the foundation for wider adoption of dCVR estimation in CVR mapping.
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Affiliation(s)
- Seyedmohammad Shams
- Rotman Research Institute, Baycrest Health Sciences, Canada; Department of Neurology, Henry Ford Health, USA
| | - Prokopis Prokopiou
- Department of Radiology, Gordon Center for Medical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | | | - J Jean Chen
- Rotman Research Institute, Baycrest Health Sciences, Canada; Department of Bioengineering, McGill University, Canada; Department of Medical Biophysics, University of Toronto, Canada; Institute of Biomedical Engineering, University of Toronto, Canada.
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13
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Mann‐Krzisnik D, Mitsis GD. Extracting electrophysiological correlates of functional magnetic resonance imaging data using the canonical polyadic decomposition. Hum Brain Mapp 2022; 43:4045-4073. [PMID: 35567768 PMCID: PMC9374895 DOI: 10.1002/hbm.25902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 04/25/2022] [Accepted: 04/27/2022] [Indexed: 11/11/2022] Open
Abstract
The relation between electrophysiology and BOLD-fMRI requires further elucidation. One approach for studying this relation is to find time-frequency features from electrophysiology that explain the variance of BOLD time-series. Convolution of these features with a canonical hemodynamic response function (HRF) is often required to model neurovascular coupling mechanisms and thus account for time shifts between electrophysiological and BOLD-fMRI data. We propose a framework for extracting the spatial distribution of these time-frequency features while also estimating more flexible, region-specific HRFs. The core component of this method is the decomposition of a tensor containing impulse response functions using the Canonical Polyadic Decomposition. The outputs of this decomposition provide insight into the relation between electrophysiology and BOLD-fMRI and can be used to construct estimates of BOLD time-series. We demonstrated the performance of this method on simulated data while also examining the effects of simulated measurement noise and physiological confounds. Afterwards, we validated our method on publicly available task-based and resting-state EEG-fMRI data. We adjusted our method to accommodate the multisubject nature of these datasets, enabling the investigation of inter-subject variability with regards to EEG-to-BOLD neurovascular coupling mechanisms. We thus also demonstrate how EEG features for modelling the BOLD signal differ across subjects.
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Affiliation(s)
- Dylan Mann‐Krzisnik
- Graduate Program in Biological and Biomedical EngineeringMcGill UniversityMontréalQuebecCanada
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14
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Prokopiou PC, Xifra-Porxas A, Kassinopoulos M, Boudrias MH, Mitsis GD. Modeling the Hemodynamic Response Function Using EEG-fMRI Data During Eyes-Open Resting-State Conditions and Motor Task Execution. Brain Topogr 2022; 35:302-321. [PMID: 35488957 DOI: 10.1007/s10548-022-00898-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 03/28/2022] [Indexed: 01/25/2023]
Abstract
Being able to accurately quantify the hemodynamic response function (HRF) that links the blood oxygen level dependent functional magnetic resonance imaging (BOLD-fMRI) signal to the underlying neural activity is important both for elucidating neurovascular coupling mechanisms and improving the accuracy of fMRI-based functional connectivity analyses. In particular, HRF estimation using BOLD-fMRI is challenging particularly in the case of resting-state data, due to the absence of information about the underlying neuronal dynamics. To this end, using simultaneously recorded electroencephalography (EEG) and fMRI data is a promising approach, as EEG provides a more direct measure of neural activations. In the present work, we employ simultaneous EEG-fMRI to investigate the regional characteristics of the HRF using measurements acquired during resting conditions. We propose a novel methodological approach based on combining distributed EEG source space reconstruction, which improves the spatial resolution of HRF estimation and using block-structured linear and nonlinear models, which enables us to simultaneously obtain HRF estimates and the contribution of different EEG frequency bands. Our results suggest that the dynamics of the resting-state BOLD signal can be sufficiently described using linear models and that the contribution of each band is region specific. Specifically, it was found that sensory-motor cortices exhibit positive HRF shapes, whereas the lateral occipital cortex and areas in the parietal cortex, such as the inferior and superior parietal lobule exhibit negative HRF shapes. To validate the proposed method, we repeated the analysis using simultaneous EEG-fMRI measurements acquired during execution of a unimanual hand-grip task. Our results reveal significant associations between BOLD signal variations and electrophysiological power fluctuations in the ipsilateral primary motor cortex, particularly for the EEG beta band, in agreement with previous studies in the literature.
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Affiliation(s)
- Prokopis C Prokopiou
- Integrated Program in Neuroscience, Montreal Neurological Institute, McGill University, Montréal, QC, H3A 2B4, Canada
| | - Alba Xifra-Porxas
- Graduate Program in Biological and Biomedical Engineering, McGill University, Montréal, QC, H3A 2B4, Canada
| | - Michalis Kassinopoulos
- Graduate Program in Biological and Biomedical Engineering, McGill University, Montréal, QC, H3A 2B4, Canada
| | - Marie-Hélène Boudrias
- Integrated Program in Neuroscience, Montreal Neurological Institute, McGill University, Montréal, QC, H3A 2B4, Canada.,School of Physical and Occupational Therapy, McGill University, Montréal, QC, H3G 1Y5, Canada.,Centre for Interdisciplinary Research in Rehabilitation of Greater Montréal (CRIR), CISSS Laval - Jewish Rehabilitation Hospital, Laval, Canada
| | - Georgios D Mitsis
- Integrated Program in Neuroscience, Montreal Neurological Institute, McGill University, Montréal, QC, H3A 2B4, Canada. .,Graduate Program in Biological and Biomedical Engineering, McGill University, Montréal, QC, H3A 2B4, Canada. .,Department of Bioengineering, McGill University, Montréal, QC, H3A 0E9, Canada.
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15
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Yan X, Boudrias MH, Mitsis GD. Removal of Transcranial Alternating Current Stimulation EEG Artifacts Using Blind Source Separation and Wavelets. IEEE Trans Biomed Eng 2022; 69:3183-3192. [PMID: 35333710 DOI: 10.1109/tbme.2022.3162490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
GOAL Transcranial alternating current stimulation (tACS) is a non-invasive technology for modulating brain activity, with significant potential for improving motor and cognitive functions. To investigate the effects of tACS, many studies have used electroencephalographic (EEG) data recorded during brain stimulation. However, the large artifacts induced by tACS make the analysis of tACS-EEG recordings challenging, which in turn has prevented the implementation of closed-loop brain stimulation schemes. Here, we propose a novel combination of blind source separation (BSS) and wavelets to achieve removal of tACS-EEG artifacts with improved performance. METHODS We examined the performance of several BSS methods both applied individually, as well as combined with the empirical wavelet transform (EWT) in terms of denoising realistic simulated and experimental tACS-EEG data. RESULTS EWT combined with BSS yielded considerably improved performance compared to BSS alone for both simulated and experimental data. Overall, independent vector analysis (IVA) combined with EWT yielded the best performance. SIGNIFICANCE The proposed method yields promise for quantifying the effects of tACS on simultaneously recorded EEG data, which can in turn contribute towards understanding the effects of tACS on brain activity, as well as extracting reliable biomarkers that may be used to develop closed-loop tACS strategies for modulating the underlying brain activity in real time.
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16
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Dimitriou NM, Flores-Torres S, Kinsella JM, Mitsis GD. Quantifying the Morphology and Mechanisms of Cancer Progression in 3D in-vitro environments: Integrating Experiments and Multiscale Models. IEEE Trans Biomed Eng 2022; 70:1318-1329. [PMID: 36264745 DOI: 10.1109/tbme.2022.3216231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Mathematical models of cancer growth have become increasingly more accurate both in the space and time domains. However, the limited amount of data typically available has resulted in a larger number of qualitative rather than quantitative studies. In the present study, we provide an integrated experimental-computational framework for the quantification of the morphological characteristics and the mechanistic modelling of cancer progression in 3D environments. The proposed framework allows for the calibration of multiscale, spatiotemporal models of cancer growth using state-of-the-art 3D cell culture data, and their validation based on the resulting experimental morphological patterns using spatial point-pattern analysis techniques. We applied this framework to the study of the development of Triple Negative Breast Cancer cells cultured in Matrigel scaffolds, and validated the hypothesis of chemotactic migration using a multiscale, hybrid Keller-Segel model. The results revealed transient, non-random spatial distributions of cancer cells that consist of clustered, and dispersion patterns. The proposed model was able to describe the general characteristics of the experimental observations and suggests that chemotactic migration together with random motion was found to be a plausible mechanism leading to accumulation, during the examined time period of development. The developed framework enabled us to pursue two goals; first, the quantitative description of the morphology of cancer growth in 3D cultures using point-pattern analysis, and second, the relation of tumour morphology with underlying biophysical mechanisms that govern cancer growth and migration.
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17
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Yan X, Mitsis GD, Boudrias MH. Identification of Beta Oscillatory Patterns During a Hand Grip Motor Task: A Comparative Analysis pre- and post-Exercise. Annu Int Conf IEEE Eng Med Biol Soc 2021; 2021:993-996. [PMID: 34891455 DOI: 10.1109/embc46164.2021.9629631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Electroencephalography (EEG) based Movement-Related Beta Band Desynchronization (MRBD) within the beta frequency band (13 - 30Hz) is commonly observed during motor task execution, and it has been associated with motor task performance. More recently, transient burst-like events termed beta bursts have been identified as another potential biomarker of motor function. Previous studies have reported decreased MRBD magnitude induced by exercise. However, little is known in terms of the effects of high-intensity exercise on beta burst patterns. In the present work, we investigated the modulatory effects of exercise on different beta burst features prior to, during and post motor task execution. We found that exercise mainly affected burst duration and burst rate within the left motor cortex area (M1) that is contralateral to the moving hand. Meanwhile, burst amplitude in the contralateral M1 area was affected differently by exercise, with smaller burst amplitude values observed during the movement preparation phase and larger magnitude during as well as post motor task execution. Since MRBD and beta burst patterns are closely associated with motor task performance, results from the present study can promote understanding about the association between exercise induced neural plasticity changes and motor performance, which can be further used for designing a subject-specific training therapy for improving motor function.
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18
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Kassinopoulos M, Mitsis GD. A multi-measure approach for assessing the performance of fMRI preprocessing strategies in resting-state functional connectivity. Magn Reson Imaging 2021; 85:228-250. [PMID: 34715292 DOI: 10.1016/j.mri.2021.10.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 09/17/2021] [Accepted: 10/17/2021] [Indexed: 12/17/2022]
Abstract
It is well established that head motion and physiological processes (e.g. cardiac and breathing activity) should be taken into consideration when analyzing and interpreting results in fMRI studies. However, even though recent studies aimed to evaluate the performance of different preprocessing pipelines there is still no consensus on the optimal strategy. This is partly due to the fact that the quality control (QC) metrics used to evaluate differences in performance across pipelines have often yielded contradictory results. Furthermore, preprocessing techniques based on physiological recordings or data decomposition techniques (e.g. aCompCor) have not been comprehensively examined. Here, to address the aforementioned issues, we propose a framework that summarizes the scores from eight previously proposed and novel QC metrics to a reduced set of two QC metrics that reflect the signal-to-noise ratio and the reduction in motion artifacts and biases in the preprocessed fMRI data. Using this framework, we evaluate the performance of three commonly used practices on the quality of data: 1) Removal of nuisance regressors from fMRI data, 2) discarding motion-contaminated volumes (i.e., scrubbing) before regression, and 3) low-pass filtering the data and the nuisance regressors before their removal. Using resting-state fMRI data from the Human Connectome Project, we show that the scores of the examined QC metrics improve the most when the global signal (GS) and about 17% of principal components from white matter (WM) are removed from the data. Finally, we observe a small further improvement with low-pass filtering at 0.20 Hz and milder variants of WM denoising, but not with scrubbing.
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Affiliation(s)
- Michalis Kassinopoulos
- Graduate Program in Biological and Biomedical Engineering, McGill University, Montreal, QC, Canada.
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, QC, Canada
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19
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Savva AD, Matsopoulos GK, Mitsis GD. A Wavelet-Based Approach for Estimating Time-Varying Connectivity in Resting-State Functional Magnetic Resonance Imaging. Brain Connect 2021; 12:285-298. [PMID: 34155908 DOI: 10.1089/brain.2021.0015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Introduction: The selection of an appropriate window size, window function, and functional connectivity (FC) metric in the sliding window method is not straightforward due to the absence of ground truth. Methods: A previously proposed wavelet-based method was accordingly adjusted for estimating time-varying FC (TVFC) and was applied to a large high-quality, low-motion dataset of 400 resting-state functional magnetic resonance imaging data. Specifically, the wavelet coherence magnitude and relative phase were averaged across wavelet (frequency) scales to yield TVFC and synchronization patterns. To assess whether the observed fluctuations in TVFC were statistically significant (dynamic FC [dFC]; the distinction between TVFC and dFC is intentional), surrogate data were generated using the multivariate phase randomization (MVPR) and multivariate autoregressive randomization (MVAR) methods to define the null hypothesis of dFC absence. Results: By averaging across all frequencies, core regions of the default mode network (DMN; medial prefrontal and posterior cingulate cortices, inferior parietal lobes, hippocampal formation) were found to exhibit dFC (test-retest reproducibility of 90%) and were also synchronized in activity (-15° ≤ phase ≤15°). When averaging across distinct frequency bands, the same dynamic connections were identified, with the majority of them identified in the frequency range (0.01, 0.198) Hz, though with lower test-retest reproducibility (<66%). Additional analysis suggested that MVPR method better preserved properties (p < 10-10), including time-averaged coherence, of the original data compared with MVAR approach. Conclusions: The wavelet-based approach identified dynamic associations between the core DMN regions with fewer choices in parameters, compared with sliding window method. Impact statement We employed a wavelet-based method, previously used in the literature, and proposed modifications to assess time-varying functional connectivity in resting-state functional magnetic resonance imaging. With this approach, dynamic connections within the default mode network were identified, involving the medial prefrontal and posterior cingulate cortices, inferior parietal lobes, and hippocampal formation, which were also highly consistent in test-retest analysis (test-retest reproducibility of 90%), without the need to select window size, window function, and functional connectivity metric as with the sliding window method, whereby no consensus on the appropriate choices of hyperparameters currently exists in the literature.
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Affiliation(s)
- Antonis D Savva
- Division of Information Transmission Systems and Material Technology, School of Electrical and Computer Engineering, National Technical University of Athens, Athens, Greece
| | - George K Matsopoulos
- Division of Information Transmission Systems and Material Technology, School of Electrical and Computer Engineering, National Technical University of Athens, Athens, Greece
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, Quebec, Canada
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20
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Kassinopoulos M, Mitsis GD. Physiological noise modeling in fMRI based on the pulsatile component of photoplethysmograph. Neuroimage 2021; 242:118467. [PMID: 34390877 DOI: 10.1016/j.neuroimage.2021.118467] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/21/2021] [Accepted: 08/10/2021] [Indexed: 02/06/2023] Open
Abstract
The blood oxygenation level-dependent (BOLD) contrast mechanism allows the noninvasive monitoring of changes in deoxyhemoglobin content. As such, it is commonly used in functional magnetic resonance imaging (fMRI) to study brain activity since levels of deoxyhemoglobin are indirectly related to local neuronal activity through neurovascular coupling mechanisms. However, the BOLD signal is severely affected by physiological processes as well as motion. Due to this, several noise correction techniques have been developed to correct for the associated confounds. The present study focuses on cardiac pulsatility fMRI confounds, aiming to refine model-based techniques that utilize the photoplethysmograph (PPG) signal. Specifically, we propose a new technique based on convolution filtering, termed cardiac pulsatility model (CPM) and compare its performance with the cardiac-related RETROICOR (Card-RETROICOR), which is a technique commonly used to model fMRI fluctuations due to cardiac pulsatility. Further, we investigate whether variations in the amplitude of the PPG pulses (PPG-Amp) covary with variations in amplitude of pulse-related fMRI fluctuations, as well as with the systemic low frequency oscillations (SLFOs) component of the fMRI global signal (GS - defined as the mean signal across all gray matter voxels). Capitalizing on 3T fMRI data from the Human Connectome Project, CPM was found to explain a significantly larger fraction of the fMRI signal variance compared to Card-RETROICOR, particularly for subjects with larger heart rate variability during the scan. The amplitude of the fMRI pulse-related fluctuations did not covary with PPG-Amp; however, PPG-Amp explained significant variance in the GS that was not attributed to variations in heart rate or breathing patterns. Our results suggest that the proposed approach can model high-frequency fluctuations due to pulsation as well as low-frequency physiological fluctuations more accurately compared to model-based techniques commonly employed in fMRI studies.
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Affiliation(s)
- Michalis Kassinopoulos
- Graduate Program in Biological and Biomedical Engineering, McGill University, Montreal, QC, Canada.
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, QC, Canada
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21
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Xifra-Porxas A, Kassinopoulos M, Mitsis GD. Physiological and motion signatures in static and time-varying functional connectivity and their subject identifiability. eLife 2021; 10:e62324. [PMID: 34342582 PMCID: PMC8378847 DOI: 10.7554/elife.62324] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 08/02/2021] [Indexed: 02/06/2023] Open
Abstract
Human brain connectivity yields significant potential as a noninvasive biomarker. Several studies have used fMRI-based connectivity fingerprinting to characterize individual patterns of brain activity. However, it is not clear whether these patterns mainly reflect neural activity or the effect of physiological and motion processes. To answer this question, we capitalize on a large data sample from the Human Connectome Project and rigorously investigate the contribution of the aforementioned processes on functional connectivity (FC) and time-varying FC, as well as their contribution to subject identifiability. We find that head motion, as well as heart rate and breathing fluctuations, induce artifactual connectivity within distinct resting-state networks and that they correlate with recurrent patterns in time-varying FC. Even though the spatiotemporal signatures of these processes yield above-chance levels in subject identifiability, removing their effects at the preprocessing stage improves identifiability, suggesting a neural component underpinning the inter-individual differences in connectivity.
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Affiliation(s)
- Alba Xifra-Porxas
- Graduate Program in Biological and Biomedical Engineering, McGill University, Montréal, Canada
| | - Michalis Kassinopoulos
- Graduate Program in Biological and Biomedical Engineering, McGill University, Montréal, Canada
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22
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Xifra-Porxas A, Ghosh A, Mitsis GD, Boudrias MH. Estimating brain age from structural MRI and MEG data: Insights from dimensionality reduction techniques. Neuroimage 2021; 231:117822. [PMID: 33549751 DOI: 10.1016/j.neuroimage.2021.117822] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 01/27/2021] [Accepted: 01/30/2021] [Indexed: 11/30/2022] Open
Abstract
Brain age prediction studies aim at reliably estimating the difference between the chronological age of an individual and their predicted age based on neuroimaging data, which has been proposed as an informative measure of disease and cognitive decline. As most previous studies relied exclusively on magnetic resonance imaging (MRI) data, we hereby investigate whether combining structural MRI with functional magnetoencephalography (MEG) information improves age prediction using a large cohort of healthy subjects (N = 613, age 18-88 years) from the Cam-CAN repository. To this end, we examined the performance of dimensionality reduction and multivariate associative techniques, namely Principal Component Analysis (PCA) and Canonical Correlation Analysis (CCA), to tackle the high dimensionality of neuroimaging data. Using MEG features (mean absolute error (MAE) of 9.60 years) yielded worse performance when compared to using MRI features (MAE of 5.33 years), but a stacking model combining both feature sets improved age prediction performance (MAE of 4.88 years). Furthermore, we found that PCA resulted in inferior performance, whereas CCA in conjunction with Gaussian process regression models yielded the best prediction performance. Notably, CCA allowed us to visualize the features that significantly contributed to brain age prediction. We found that MRI features from subcortical structures were more reliable age predictors than cortical features, and that spectral MEG measures were more reliable than connectivity metrics. Our results provide an insight into the underlying processes that are reflective of brain aging, yielding promise for the identification of reliable biomarkers of neurodegenerative diseases that emerge later during the lifespan.
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Affiliation(s)
- Alba Xifra-Porxas
- Graduate Program in Biological and Biomedical Engineering, McGill University, Montréal, Canada; Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montréal, Canada
| | - Arna Ghosh
- Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montréal, Canada; Integrated Program in Neuroscience, McGill University, Montréal, Canada
| | | | - Marie-Hélène Boudrias
- Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montréal, Canada; School of Physical and Occupational Therapy, McGill University, Montréal, Canada.
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Ezra M, Garry P, Rowland MJ, Mitsis GD, Pattinson KT. Phase dynamics of cerebral blood flow in subarachnoid haemorrhage in response to sodium nitrite infusion. Nitric Oxide 2020; 106:55-65. [PMID: 33283760 DOI: 10.1016/j.niox.2020.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 10/08/2020] [Accepted: 10/18/2020] [Indexed: 11/25/2022]
Abstract
Aneurysmal subarachnoid haemorrhage (SAH) is a devastating subset of stroke. One of the major determinates of morbidity is the development of delayed cerebral ischemia (DCI). Disruption of the nitric oxide (NO) pathway and consequently the control of cerebral blood flow (CBF), known as cerebral autoregulation, is believed to play a role in its pathophysiology. Through the pharmacological manipulation of in vivo NO levels using an exogenous NO donor we sought to explore this relationship. Phase synchronisation index (PSI), an expression of the interdependence between CBF and arterial blood pressure (ABP) and thus cerebral autoregulation, was calculated before and during sodium nitrite administration in 10 high-grade SAH patients acutely post-rupture. In patients that did not develop DCI, there was a significant increase in PSI around 0.1 Hz during the administration of sodium nitrite (33%; p-value 0.006). In patients that developed DCI, PSI did not change significantly. Synchronisation between ABP and CBF at 0.1 Hz has been proposed as a mechanism by which organ perfusion is maintained, during periods of physiological stress. These findings suggest that functional NO depletion plays a role in impaired cerebral autoregulation following SAH, but the development of DCI may have a distinct pathophysiological aetiology.
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Affiliation(s)
- Martyn Ezra
- Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, UK.
| | - Payashi Garry
- Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, UK
| | - Matthew J Rowland
- Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, UK
| | | | - Kyle Ts Pattinson
- Nuffield Division of Anaesthetics, Nuffield Department of Clinical Neurosciences, University of Oxford, UK
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Yan X, Boudrias MH, Mitsis GD. Artifact Removal in tACS-EEG Recordings: A Combined Methodology Based on the Empirical Wavelet Transform. Annu Int Conf IEEE Eng Med Biol Soc 2020; 2020:944-947. [PMID: 33018140 DOI: 10.1109/embc44109.2020.9176488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Transcranial alternating current stimulation (tACS) is a non-invasive brain stimulation technique that modulates brain activity, which yields promise for achieving desired behavioral outcomes in different contexts. Combining tACS with electroencephalography (EEG) allows for the monitoring of the real-time effects of stimulation. However, the EEG signal recorded with simultaneous tACS is largely contaminated by stimulation-induced artifacts. In this work, we examine the combination of the empirical wavelet transform (EWT) with three blind source separation (BSS) methods: principal component analysis (PCA), multiset canonical correlation analysis (MCCA) and independent vector analysis (IVA), aiming to remove artifacts in tACS-contaminated EEG recordings. Using simulated data, we show that EWT followed by IVA achieves the best performance. Using experimental data, we show that BSS combined with EWT performs better compared to standard BSS methodology in terms of preserving useful information while eliminating artifacts.
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Mann-Krzisnik DW, Mitsis GD. Modeling BOLD-fMRI Hemodynamics via Multidimensional Decomposition of Electrophysiology Data: A Simulation Study. Annu Int Conf IEEE Eng Med Biol Soc 2020; 2020:398-401. [PMID: 33018012 DOI: 10.1109/embc44109.2020.9175469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We propose a framework for studying the electrophysiological correlates of BOLD-fMRI. This framework relies on structured coupled matrix-tensor factorization (sCMTF), a joint multidimensional decomposition which reveals dynamical interactions between LFP/EEG oscillatory features and BOLD-fMRI data. We test whether LFP/EEG-BOLD co-fluctuations and regional hemodynamic response functions can be estimated by sCMTF using whole-brain modelling of restingstate activity. We produce permuted datasets to show that our framework extracts EEG/LFP temporal patterns that correlate significantly with BOLD signal fluctuations. Our framework is also capable of estimating HRFs that accurately embodies simulated hemodynamics, with a word of caution regarding initialization of the sCMTF algorithm.
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Botvinik-Nezer R, Holzmeister F, Camerer CF, Dreber A, Huber J, Johannesson M, Kirchler M, Iwanir R, Mumford JA, Adcock RA, Avesani P, Baczkowski BM, Bajracharya A, Bakst L, Ball S, Barilari M, Bault N, Beaton D, Beitner J, Benoit RG, Berkers RMWJ, Bhanji JP, Biswal BB, Bobadilla-Suarez S, Bortolini T, Bottenhorn KL, Bowring A, Braem S, Brooks HR, Brudner EG, Calderon CB, Camilleri JA, Castrellon JJ, Cecchetti L, Cieslik EC, Cole ZJ, Collignon O, Cox RW, Cunningham WA, Czoschke S, Dadi K, Davis CP, Luca AD, Delgado MR, Demetriou L, Dennison JB, Di X, Dickie EW, Dobryakova E, Donnat CL, Dukart J, Duncan NW, Durnez J, Eed A, Eickhoff SB, Erhart A, Fontanesi L, Fricke GM, Fu S, Galván A, Gau R, Genon S, Glatard T, Glerean E, Goeman JJ, Golowin SAE, González-García C, Gorgolewski KJ, Grady CL, Green MA, Guassi Moreira JF, Guest O, Hakimi S, Hamilton JP, Hancock R, Handjaras G, Harry BB, Hawco C, Herholz P, Herman G, Heunis S, Hoffstaedter F, Hogeveen J, Holmes S, Hu CP, Huettel SA, Hughes ME, Iacovella V, Iordan AD, Isager PM, Isik AI, Jahn A, Johnson MR, Johnstone T, Joseph MJE, Juliano AC, Kable JW, Kassinopoulos M, Koba C, Kong XZ, Koscik TR, Kucukboyaci NE, Kuhl BA, Kupek S, Laird AR, Lamm C, Langner R, Lauharatanahirun N, Lee H, Lee S, Leemans A, Leo A, Lesage E, Li F, Li MYC, Lim PC, Lintz EN, Liphardt SW, Losecaat Vermeer AB, Love BC, Mack ML, Malpica N, Marins T, Maumet C, McDonald K, McGuire JT, Melero H, Méndez Leal AS, Meyer B, Meyer KN, Mihai G, Mitsis GD, Moll J, Nielson DM, Nilsonne G, Notter MP, Olivetti E, Onicas AI, Papale P, Patil KR, Peelle JE, Pérez A, Pischedda D, Poline JB, Prystauka Y, Ray S, Reuter-Lorenz PA, Reynolds RC, Ricciardi E, Rieck JR, Rodriguez-Thompson AM, Romyn A, Salo T, Samanez-Larkin GR, Sanz-Morales E, Schlichting ML, Schultz DH, Shen Q, Sheridan MA, Silvers JA, Skagerlund K, Smith A, Smith DV, Sokol-Hessner P, Steinkamp SR, Tashjian SM, Thirion B, Thorp JN, Tinghög G, Tisdall L, Tompson SH, Toro-Serey C, Torre Tresols JJ, Tozzi L, Truong V, Turella L, van 't Veer AE, Verguts T, Vettel JM, Vijayarajah S, Vo K, Wall MB, Weeda WD, Weis S, White DJ, Wisniewski D, Xifra-Porxas A, Yearling EA, Yoon S, Yuan R, Yuen KSL, Zhang L, Zhang X, Zosky JE, Nichols TE, Poldrack RA, Schonberg T. Variability in the analysis of a single neuroimaging dataset by many teams. Nature 2020; 582:84-88. [PMID: 32483374 PMCID: PMC7771346 DOI: 10.1038/s41586-020-2314-9] [Citation(s) in RCA: 423] [Impact Index Per Article: 105.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 04/07/2020] [Indexed: 01/13/2023]
Abstract
Data analysis workflows in many scientific domains have become increasingly complex and flexible. Here we assess the effect of this flexibility on the results of functional magnetic resonance imaging by asking 70 independent teams to analyse the same dataset, testing the same 9 ex-ante hypotheses1. The flexibility of analytical approaches is exemplified by the fact that no two teams chose identical workflows to analyse the data. This flexibility resulted in sizeable variation in the results of hypothesis tests, even for teams whose statistical maps were highly correlated at intermediate stages of the analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Notably, a meta-analytical approach that aggregated information across teams yielded a significant consensus in activated regions. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset2-5. Our findings show that analytical flexibility can have substantial effects on scientific conclusions, and identify factors that may be related to variability in the analysis of functional magnetic resonance imaging. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for performing and reporting multiple analyses of the same data. Potential approaches that could be used to mitigate issues related to analytical variability are discussed.
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Affiliation(s)
- Rotem Botvinik-Nezer
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH, USA
| | - Felix Holzmeister
- Department of Banking and Finance, University of Innsbruck, Innsbruck, Austria
| | - Colin F Camerer
- HSS and CNS, California Institute of Technology, Pasadena, CA, USA
| | - Anna Dreber
- Department of Economics, Stockholm School of Economics, Stockholm, Sweden
- Department of Economics, University of Innsbruck, Innsbruck, Austria
| | - Juergen Huber
- Department of Banking and Finance, University of Innsbruck, Innsbruck, Austria
| | - Magnus Johannesson
- Department of Economics, Stockholm School of Economics, Stockholm, Sweden
| | - Michael Kirchler
- Department of Banking and Finance, University of Innsbruck, Innsbruck, Austria
| | - Roni Iwanir
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Jeanette A Mumford
- Center for Healthy Minds, University of Wisconsin-Madison, Madison, WI, USA
| | - R Alison Adcock
- Center for Cognitive Neuroscience, Duke University, Durham, NC, USA
- Department of Psychiatry and Behavioral Sciences, Duke University, Durham, NC, USA
| | - Paolo Avesani
- Neuroinformatics Laboratory, Fondazione Bruno Kessler, Trento, Italy
- Center for Mind/Brain Sciences - CIMeC, University of Trento, Rovereto, Italy
| | - Blazej M Baczkowski
- Department of Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Aahana Bajracharya
- Department of Otolaryngology, Washington University in St. Louis, St. Louis, MO, USA
| | - Leah Bakst
- Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
- Center for Systems Neuroscience, Boston University, Boston, MA, USA
| | - Sheryl Ball
- Department of Economics, Virginia Tech, Blacksburg, VA, USA
- School of Neuroscience, Virginia Tech, Blacksburg, VA, USA
| | - Marco Barilari
- Crossmodal Perception and Plasticity Laboratory, Institutes for Research in Psychology (IPSY) and Neurosciences (IoNS), UCLouvain, Louvain-la-Neuve, Belgium
| | - Nadège Bault
- School of Psychology, University of Plymouth, Plymouth, UK
| | - Derek Beaton
- Rotman Research Institute, Baycrest Health Sciences Centre, Toronto, Ontario, Canada
| | - Julia Beitner
- Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands
- Department of Psychology, Goethe University, Frankfurt am Main, Germany
| | - Roland G Benoit
- Max Planck Research Group: Adaptive Memory, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Ruud M W J Berkers
- Max Planck Research Group: Adaptive Memory, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Jamil P Bhanji
- Department of Psychology, Rutgers University-Newark, Newark, NJ, USA
| | - Bharat B Biswal
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ, USA
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | | | - Tiago Bortolini
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil
| | | | - Alexander Bowring
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Population Health, University of Oxford, Oxford, UK
| | - Senne Braem
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
- Department of Psychology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Hayley R Brooks
- Department of Psychology, University of Denver, Denver, CO, USA
| | - Emily G Brudner
- Department of Psychology, Rutgers University-Newark, Newark, NJ, USA
| | | | - Julia A Camilleri
- Institute of Neuroscience and Medicine, Brain and Behaviour (INM-7), Research Centre Jülich, Jülich, Germany
- Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Jaime J Castrellon
- Center for Cognitive Neuroscience, Duke University, Durham, NC, USA
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
| | - Luca Cecchetti
- MoMiLab Research Unit, IMT School for Advanced Studies Lucca, Lucca, Italy
| | - Edna C Cieslik
- Institute of Neuroscience and Medicine, Brain and Behaviour (INM-7), Research Centre Jülich, Jülich, Germany
- Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Zachary J Cole
- Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Olivier Collignon
- Center for Mind/Brain Sciences - CIMeC, University of Trento, Rovereto, Italy
- Crossmodal Perception and Plasticity Laboratory, Institutes for Research in Psychology (IPSY) and Neurosciences (IoNS), UCLouvain, Louvain-la-Neuve, Belgium
| | - Robert W Cox
- National Institute of Mental Health (NIMH), National Institutes of Health, Bethesda, MD, USA
| | | | - Stefan Czoschke
- Institute of Medical Psychology, Goethe University, Frankfurt am Main, Germany
| | | | - Charles P Davis
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, USA
- Brain Imaging Research Center, University of Connecticut, Storrs, CT, USA
- Connecticut Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, CT, USA
| | - Alberto De Luca
- PROVIDI Lab, Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Lysia Demetriou
- Section of Endocrinology and Investigative Medicine, Faculty of Medicine, Imperial College London, London, UK
- Nuffield Department of Women's and Reproductive Health, University of Oxford, Oxford, UK
| | | | - Xin Di
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ, USA
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Erin W Dickie
- Krembil Centre for Neuroinformatics, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Ekaterina Dobryakova
- Center for Traumatic Brain Injury Research, Kessler Foundation, East Hanover, NJ, USA
| | - Claire L Donnat
- Department of Statistics, Stanford University, Stanford, CA, USA
| | - Juergen Dukart
- Institute of Neuroscience and Medicine, Brain and Behaviour (INM-7), Research Centre Jülich, Jülich, Germany
- Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Niall W Duncan
- Graduate Institute of Mind, Brain and Consciousness, Taipei Medical University, Taipei, Taiwan
- Brain and Consciousness Research Centre, TMU-ShuangHo Hospital, New Taipei City, Taiwan
| | - Joke Durnez
- Department of Psychology and Stanford Center for Reproducible Neuroscience, Stanford University, Stanford, CA, USA
| | - Amr Eed
- Instituto de Neurociencias, CSIC-UMH, Alicante, Spain
| | - Simon B Eickhoff
- Institute of Neuroscience and Medicine, Brain and Behaviour (INM-7), Research Centre Jülich, Jülich, Germany
- Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Andrew Erhart
- Department of Psychology, University of Denver, Denver, CO, USA
| | - Laura Fontanesi
- Faculty of Psychology, University of Basel, Basel, Switzerland
| | - G Matthew Fricke
- Computer Science Department, University of New Mexico, Albuquerque, NM, USA
| | - Shiguang Fu
- School of Management, Zhejiang University of Technology, Hangzhou, China
- Institute of Neuromanagement, Zhejiang University of Technology, Hangzhou, China
| | - Adriana Galván
- Department of Psychology, University of California Los Angeles, Los Angeles, CA, USA
| | - Remi Gau
- Crossmodal Perception and Plasticity Laboratory, Institutes for Research in Psychology (IPSY) and Neurosciences (IoNS), UCLouvain, Louvain-la-Neuve, Belgium
| | - Sarah Genon
- Institute of Neuroscience and Medicine, Brain and Behaviour (INM-7), Research Centre Jülich, Jülich, Germany
- Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Tristan Glatard
- Department of Computer Science and Software Engineering, Concordia University, Montreal, Quebec, Canada
| | - Enrico Glerean
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
| | - Jelle J Goeman
- Department of Biomedical Data Sciences, Leiden University Medical Center, Leiden, The Netherlands
| | - Sergej A E Golowin
- Graduate Institute of Mind, Brain and Consciousness, Taipei Medical University, Taipei, Taiwan
| | | | | | - Cheryl L Grady
- Rotman Research Institute, Baycrest Health Sciences Centre, Toronto, Ontario, Canada
| | - Mikella A Green
- Center for Cognitive Neuroscience, Duke University, Durham, NC, USA
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
| | - João F Guassi Moreira
- Department of Psychology, University of California Los Angeles, Los Angeles, CA, USA
| | - Olivia Guest
- Department of Experimental Psychology, University College London, London, UK
- Research Centre on Interactive Media, Smart Systems and Emerging Technologies - RISE, Nicosia, Cyprus
| | - Shabnam Hakimi
- Center for Cognitive Neuroscience, Duke University, Durham, NC, USA
| | - J Paul Hamilton
- Center for Social and Affective Neuroscience, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Roeland Hancock
- Brain Imaging Research Center, University of Connecticut, Storrs, CT, USA
- Connecticut Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, CT, USA
| | - Giacomo Handjaras
- MoMiLab Research Unit, IMT School for Advanced Studies Lucca, Lucca, Italy
| | - Bronson B Harry
- The MARCS Institute for Brain, Behaviour and Development, Western Sydney University, Sydney, New South Wales, Australia
| | - Colin Hawco
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Peer Herholz
- McConnell Brain Imaging Centre, The Neuro (Montreal Neurological Institute-Hospital), Faculty of Medicine, McGill University, Montreal, Quebec, Canada
| | - Gabrielle Herman
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Stephan Heunis
- Department of Electrical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Department of Research and Development, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands
| | - Felix Hoffstaedter
- Institute of Neuroscience and Medicine, Brain and Behaviour (INM-7), Research Centre Jülich, Jülich, Germany
- Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Jeremy Hogeveen
- Department of Psychology, University of New Mexico, Albuquerque, NM, USA
- Psychology Clinical Neuroscience Center, University of New Mexico, Albuquerque, NM, USA
| | - Susan Holmes
- Department of Statistics, Stanford University, Stanford, CA, USA
| | - Chuan-Peng Hu
- Leibniz-Institut für Resilienzforschung (LIR), Mainz, Germany
| | - Scott A Huettel
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
| | - Matthew E Hughes
- School of Health Sciences, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Vittorio Iacovella
- Center for Mind/Brain Sciences - CIMeC, University of Trento, Rovereto, Italy
| | | | - Peder M Isager
- Department of Industrial Engineering and Innovation Sciences, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Ayse I Isik
- Department of Neuroscience, Max Planck Institute for Empirical Aesthetics, Frankfurt am Main, Germany
| | - Andrew Jahn
- fMRI Laboratory, University of Michigan, Ann Arbor, MI, USA
| | - Matthew R Johnson
- Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE, USA
- Center for Brain, Biology and Behavior, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Tom Johnstone
- School of Health Sciences, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - Michael J E Joseph
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Anthony C Juliano
- Center for Neuropsychology and Neuroscience Research, Kessler Foundation, East Hanover, NJ, USA
| | - Joseph W Kable
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
- MindCORE, University of Pennsylvania, Philadelphia, PA, USA
| | - Michalis Kassinopoulos
- Graduate Program in Biological and Biomedical Engineering, McGill University, Montreal, Quebec, Canada
| | - Cemal Koba
- MoMiLab Research Unit, IMT School for Advanced Studies Lucca, Lucca, Italy
| | - Xiang-Zhen Kong
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
| | - Timothy R Koscik
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Nuri Erkut Kucukboyaci
- Center for Traumatic Brain Injury Research, Kessler Foundation, East Hanover, NJ, USA
- Department of Physical Medicine and Rehabilitation, Rutgers New Jersey Medical School, Newark, NJ, USA
| | - Brice A Kuhl
- Department of Psychology, University of Oregon, Eugene, OR, USA
| | - Sebastian Kupek
- Faculty of Economics and Statistics, University of Innsbruck, Innsbruck, Austria
| | - Angela R Laird
- Department of Physics, Florida International University, Miami, Florida, USA
| | - Claus Lamm
- Department of Cognition, Emotion, and Methods in Psychology, Faculty of Psychology, University of Vienna, Vienna, Austria
- Vienna Cognitive Science Hub, University of Vienna, Vienna, Austria
| | - Robert Langner
- Institute of Neuroscience and Medicine, Brain and Behaviour (INM-7), Research Centre Jülich, Jülich, Germany
- Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Nina Lauharatanahirun
- US CCDC Army Research Laboratory, Human Research and Engineering Directorate, Aberdeen Proving Ground, MD, USA
- Annenberg School for Communication, University of Pennsylvania, Philadelphia, PA, USA
| | - Hongmi Lee
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, USA
| | - Sangil Lee
- Department of Psychology, University of Pennsylvania, Philadelphia, PA, USA
| | - Alexander Leemans
- PROVIDI Lab, Image Sciences Institute, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Andrea Leo
- MoMiLab Research Unit, IMT School for Advanced Studies Lucca, Lucca, Italy
| | - Elise Lesage
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
| | - Flora Li
- Fralin Biomedical Research Institute, Roanoke, VA, USA
- Economics Experimental Lab, Nanjing Audit University, Nanjing, China
| | - Monica Y C Li
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, USA
- Brain Imaging Research Center, University of Connecticut, Storrs, CT, USA
- Connecticut Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, CT, USA
- Haskins Laboratories, New Haven, CT, USA
| | - Phui Cheng Lim
- Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE, USA
- Center for Brain, Biology and Behavior, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Evan N Lintz
- Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | | | - Annabel B Losecaat Vermeer
- Department of Cognition, Emotion, and Methods in Psychology, Faculty of Psychology, University of Vienna, Vienna, Austria
| | - Bradley C Love
- Department of Experimental Psychology, University College London, London, UK
- The Alan Turing Institute, London, UK
| | - Michael L Mack
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Norberto Malpica
- Laboratorio de Análisis de Imagen Médica y Biometría (LAIMBIO), Universidad Rey Juan Carlos, Madrid, Spain
| | - Theo Marins
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil
| | - Camille Maumet
- Inria, Univ Rennes, CNRS, Inserm, IRISA UMR 6074, Empenn ERL U 1228, Rennes, France
| | - Kelsey McDonald
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
| | - Joseph T McGuire
- Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
- Center for Systems Neuroscience, Boston University, Boston, MA, USA
| | - Helena Melero
- Laboratorio de Análisis de Imagen Médica y Biometría (LAIMBIO), Universidad Rey Juan Carlos, Madrid, Spain
- Departamento de Psicobiología, División de Psicología, CES Cardenal Cisneros, Madrid, Spain
- Northeastern University Biomedical Imaging Center, Northeastern University, Boston, MA, USA
| | - Adriana S Méndez Leal
- Department of Psychology, University of California Los Angeles, Los Angeles, CA, USA
| | - Benjamin Meyer
- Leibniz-Institut für Resilienzforschung (LIR), Mainz, Germany
- Neuroimaging Center (NIC), Focus Program Translational Neurosciences (FTN), Johannes Gutenberg University Medical Center Mainz, Mainz, Germany
| | - Kristin N Meyer
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Glad Mihai
- Max Planck Research Group: Neural Mechanisms of Human Communication, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
- Chair of Cognitive and Clinical Neuroscience, Faculty of Psychology, Technische Universität Dresden, Dresden, Germany
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, Quebec, Canada
| | - Jorge Moll
- D'Or Institute for Research and Education (IDOR), Rio de Janeiro, Brazil
- Department of Psychology, Stanford University, Stanford, CA, USA
| | - Dylan M Nielson
- Data Science and Sharing Team, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Gustav Nilsonne
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Department of Psychology, Stockholm University, Stockholm, Sweden
| | - Michael P Notter
- The Laboratory for Investigative Neurophysiology (The LINE), Department of Radiology, University Hospital Center and University of Lausanne, Lausanne, Switzerland
| | - Emanuele Olivetti
- Neuroinformatics Laboratory, Fondazione Bruno Kessler, Trento, Italy
- Center for Mind/Brain Sciences - CIMeC, University of Trento, Rovereto, Italy
| | - Adrian I Onicas
- MoMiLab Research Unit, IMT School for Advanced Studies Lucca, Lucca, Italy
| | - Paolo Papale
- MoMiLab Research Unit, IMT School for Advanced Studies Lucca, Lucca, Italy
- Department of Vision and Cognition, Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - Kaustubh R Patil
- Institute of Neuroscience and Medicine, Brain and Behaviour (INM-7), Research Centre Jülich, Jülich, Germany
- Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Jonathan E Peelle
- Department of Otolaryngology, Washington University in St. Louis, St. Louis, MO, USA
| | - Alexandre Pérez
- McConnell Brain Imaging Centre, The Neuro (Montreal Neurological Institute-Hospital), Faculty of Medicine, McGill University, Montreal, Quebec, Canada
| | - Doris Pischedda
- Bernstein Center for Computational Neuroscience and Berlin Center for Advanced Neuroimaging and Clinic for Neurology, Charité Universitätsmedizin, corporate member of Freie Universität Berlin, Humboldt Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Cluster of Excellence Science of Intelligence, Technische Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
- NeuroMI - Milan Center for Neuroscience, Milan, Italy
| | - Jean-Baptiste Poline
- McConnell Brain Imaging Centre, The Neuro (Montreal Neurological Institute-Hospital), Faculty of Medicine, McGill University, Montreal, Quebec, Canada
- Henry H. Wheeler, Jr. Brain Imaging Center, Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, USA
| | - Yanina Prystauka
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, USA
- Brain Imaging Research Center, University of Connecticut, Storrs, CT, USA
- Connecticut Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, CT, USA
| | - Shruti Ray
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ, USA
| | | | - Richard C Reynolds
- Scientific and Statistical Computing Core, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Emiliano Ricciardi
- MoMiLab Research Unit, IMT School for Advanced Studies Lucca, Lucca, Italy
| | - Jenny R Rieck
- Rotman Research Institute, Baycrest Health Sciences Centre, Toronto, Ontario, Canada
| | - Anais M Rodriguez-Thompson
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Anthony Romyn
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Taylor Salo
- Department of Psychology, Florida International University, Miami, FL, USA
| | - Gregory R Samanez-Larkin
- Center for Cognitive Neuroscience, Duke University, Durham, NC, USA
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
| | - Emilio Sanz-Morales
- Laboratorio de Análisis de Imagen Médica y Biometría (LAIMBIO), Universidad Rey Juan Carlos, Madrid, Spain
| | | | - Douglas H Schultz
- Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE, USA
- Center for Brain, Biology and Behavior, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Qiang Shen
- School of Management, Zhejiang University of Technology, Hangzhou, China
- Institute of Neuromanagement, Zhejiang University of Technology, Hangzhou, China
| | - Margaret A Sheridan
- Department of Psychology and Neuroscience, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jennifer A Silvers
- Department of Psychology, University of California Los Angeles, Los Angeles, CA, USA
| | - Kenny Skagerlund
- Department of Behavioural Sciences and Learning, Linköping University, Linköping, Sweden
- Center for Social and Affective Neuroscience, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Alec Smith
- Department of Economics, Virginia Tech, Blacksburg, VA, USA
- School of Neuroscience, Virginia Tech, Blacksburg, VA, USA
| | - David V Smith
- Department of Psychology, Temple University, Philadelphia, PA, USA
| | | | - Simon R Steinkamp
- Institute of Neuroscience and Medicine, Cognitive Neuroscience (INM-3), Research Centre Jülich, Jülich, Germany
| | - Sarah M Tashjian
- Department of Psychology, University of California Los Angeles, Los Angeles, CA, USA
| | | | - John N Thorp
- Department of Psychology, Columbia University, New York, NY, USA
| | - Gustav Tinghög
- Department of Management and Engineering, Linköping University, Linköping, Sweden
- Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Loreen Tisdall
- Department of Psychology, Stanford University, Stanford, CA, USA
- Center for Cognitive and Decision Sciences, University of Basel, Basel, Switzerland
| | - Steven H Tompson
- US CCDC Army Research Laboratory, Human Research and Engineering Directorate, Aberdeen Proving Ground, MD, USA
| | - Claudio Toro-Serey
- Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA
- Center for Systems Neuroscience, Boston University, Boston, MA, USA
| | | | - Leonardo Tozzi
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Vuong Truong
- Graduate Institute of Mind, Brain and Consciousness, Taipei Medical University, Taipei, Taiwan
- Brain and Consciousness Research Centre, TMU-ShuangHo Hospital, New Taipei City, Taiwan
| | - Luca Turella
- Center for Mind/Brain Sciences - CIMeC, University of Trento, Rovereto, Italy
| | - Anna E van 't Veer
- Methodology and Statistics Unit, Institute of Psychology, Leiden University, Leiden, The Netherlands
| | - Tom Verguts
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
| | - Jean M Vettel
- US Combat Capabilities Development Command Army Research Laboratory, Aberdeen, MD, USA
- University of California Santa Barbara, Santa Barbara, CA, USA
- University of Pennsylvania, Philadelphia, PA, USA
| | - Sagana Vijayarajah
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Khoi Vo
- Center for Cognitive Neuroscience, Duke University, Durham, NC, USA
- Department of Psychology and Neuroscience, Duke University, Durham, NC, USA
| | - Matthew B Wall
- Invicro, London, UK
- Faculty of Medicine, Imperial College London, London, UK
- Clinical Psychopharmacology Unit, University College London, London, UK
| | - Wouter D Weeda
- Methodology and Statistics Unit, Institute of Psychology, Leiden University, Leiden, The Netherlands
| | - Susanne Weis
- Institute of Neuroscience and Medicine, Brain and Behaviour (INM-7), Research Centre Jülich, Jülich, Germany
- Institute of Systems Neuroscience, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - David J White
- Centre for Human Psychopharmacology, Swinburne University, Hawthorn, Victoria, Australia
| | - David Wisniewski
- Department of Experimental Psychology, Ghent University, Ghent, Belgium
| | - Alba Xifra-Porxas
- Graduate Program in Biological and Biomedical Engineering, McGill University, Montreal, Quebec, Canada
| | - Emily A Yearling
- Department of Psychological Sciences, University of Connecticut, Storrs, CT, USA
- Brain Imaging Research Center, University of Connecticut, Storrs, CT, USA
- Connecticut Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, CT, USA
| | - Sangsuk Yoon
- Department of Management and Marketing, School of Business, University of Dayton, Dayton, OH, USA
| | - Rui Yuan
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Kenneth S L Yuen
- Leibniz-Institut für Resilienzforschung (LIR), Mainz, Germany
- Neuroimaging Center (NIC), Focus Program Translational Neurosciences (FTN), Johannes Gutenberg University Medical Center Mainz, Mainz, Germany
| | - Lei Zhang
- Department of Cognition, Emotion, and Methods in Psychology, Faculty of Psychology, University of Vienna, Vienna, Austria
| | - Xu Zhang
- Brain Imaging Research Center, University of Connecticut, Storrs, CT, USA
- Connecticut Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, CT, USA
- Biomedical Engineering Department, University of Connecticut, Storrs, CT, USA
| | - Joshua E Zosky
- Department of Psychology, University of Nebraska-Lincoln, Lincoln, NE, USA
- Center for Brain, Biology and Behavior, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Thomas E Nichols
- Oxford Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Nuffield Department of Population Health, University of Oxford, Oxford, UK.
| | | | - Tom Schonberg
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
- Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
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Patmanidis S, Charalampidis AC, Kordonis I, Strati K, Mitsis GD, Papavassilopoulos GP. Individualized growth prediction of mice skin tumors with maximum likelihood estimators. Comput Methods Programs Biomed 2020; 185:105165. [PMID: 31710982 DOI: 10.1016/j.cmpb.2019.105165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 10/11/2019] [Accepted: 10/29/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND & OBJECTIVE In this work, we focus on estimating the parameters of the Gompertz model in order to predict tumor growth. The estimation is based on measurements from mice skin tumors of de novo carcinogenesis. The main objective is to compare the Maximum Likelihood estimator with the best performance from our previous work with the Non-linear Least Squares estimator which is commonly used in the literature to estimate the growth parameters of the Gompertz model. METHODS To describe tumor growth, we propose a stochastic model which is based on the Gompertz growth function. The principle of Maximum Likelihood is used to estimate both the growth rate and the carrying capacity of the Gompertz function, along with the characteristics of the additive Gaussian process and measurement noise. Moreover, we examine whether a Maximum A Posteriori estimator is able to utilize any available prior knowledge in order to improve the predictions. RESULTS Experimental data from a total of 24 tumors in 8 mice (3 tumors each) were used to study the performance of the proposed methods with respect to prediction accuracy. Our results show that the Maximum Likelihood estimator is able to provide, in most cases, more accurate predictions. Moreover, the Maximum A Posteriori estimator has the potential to correct potentially non-realistic estimates for the carrying capacity at early growth stages. CONCLUSION In most cases, the Maximum Likelihood estimator is able to provide more reliable predictions for the tumor's growth on individual test subjects. The Maximum A Posteriori estimator, it has the potential to improve the prediction when the available experimental data do not provide adequate information by utilizing prior knowledge about the unknown parameters.
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Affiliation(s)
- Spyridon Patmanidis
- School of Electrical and Computer Engineering, National Technical University of Athens, Iroon Polytechneiou 9, Zografou 15780, Athens, Greece.
| | - Alexandros C Charalampidis
- Department of Electrical Engineering and Computer Science, Technische Universität Berlin, Einsteinufer 17, Berlin D-10587, Germany; CentraleSupélec, Avenue de la Boulaie, 35576 Cesson-Sévigné, France.
| | - Ioannis Kordonis
- CentraleSupélec, Avenue de la Boulaie, 35576 Cesson-Sévigné, France
| | - Katerina Strati
- Department of Biological Sciences, University of Cyprus, Panepistimiou 1, Aglantzia 2109, Nicosia, Cyprus.
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, 817 Sherbrooke Ave W, MacDonald Engineering Building 270, Montréal QC H3A 0C3, Canada.
| | - George P Papavassilopoulos
- School of Electrical and Computer Engineering, National Technical University of Athens, Iroon Polytechneiou 9, Zografou 15780, Athens, Greece.
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28
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Mitsis GD, Anastasiadou MN, Christodoulakis M, Papathanasiou ES, Papacostas SS, Hadjipapas A. Functional brain networks of patients with epilepsy exhibit pronounced multiscale periodicities, which correlate with seizure onset. Hum Brain Mapp 2020; 41:2059-2076. [PMID: 31977145 PMCID: PMC7268013 DOI: 10.1002/hbm.24930] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 12/11/2019] [Accepted: 01/07/2020] [Indexed: 11/08/2022] Open
Abstract
Epileptic seizure detection and prediction by using noninvasive measurements such as scalp EEG signals or invasive, intracranial recordings, has been at the heart of epilepsy studies for at least three decades. To this end, the most common approach has been to consider short‐length recordings (several seconds to a few minutes) around a seizure, aiming to identify significant changes that occur before or during seizures. An inherent assumption in this approach is the presence of a relatively constant EEG activity in the interictal period, which is interrupted by seizure occurrence. Here, we examine this assumption by using long‐duration scalp EEG data (21–94 hr) in nine patients with epilepsy, based on which we construct functional brain networks. Our results reveal that these networks vary over time in a periodic fashion, exhibiting multiple peaks at periods ranging between 1 and 24 hr. The effects of seizure onset on the functional brain network properties were found to be considerably smaller in magnitude compared to the changes due to these inherent periodic cycles. Importantly, the properties of the identified network periodic components (instantaneous phase) were found to be strongly correlated to seizure onset, especially for the periodicities around 3 and 5 hr. These correlations were found to be largely absent between EEG signal periodicities and seizure onset, suggesting that higher specificity may be achieved by using network‐based metrics. In turn, this implies that more robust seizure detection and prediction can be achieved if longer term underlying functional brain network periodic variations are taken into account.
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Affiliation(s)
| | | | | | | | - Savvas S Papacostas
- Neurology Clinic B, Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
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29
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Elting JW, Sanders ML, Panerai RB, Aries M, Bor-Seng-Shu E, Caicedo A, Chacon M, Gommer ED, Van Huffel S, Jara JL, Kostoglou K, Mahdi A, Marmarelis VZ, Mitsis GD, Müller M, Nikolic D, Nogueira RC, Payne SJ, Puppo C, Shin DC, Simpson DM, Tarumi T, Yelicich B, Zhang R, Claassen JAHR. Assessment of dynamic cerebral autoregulation in humans: Is reproducibility dependent on blood pressure variability? PLoS One 2020; 15:e0227651. [PMID: 31923919 PMCID: PMC6954074 DOI: 10.1371/journal.pone.0227651] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 12/22/2019] [Indexed: 01/02/2023] Open
Abstract
We tested the influence of blood pressure variability on the reproducibility of dynamic cerebral autoregulation (DCA) estimates. Data were analyzed from the 2nd CARNet bootstrap initiative, where mean arterial blood pressure (MABP), cerebral blood flow velocity (CBFV) and end tidal CO2 were measured twice in 75 healthy subjects. DCA was analyzed by 14 different centers with a variety of different analysis methods. Intraclass Correlation (ICC) values increased significantly when subjects with low power spectral density MABP (PSD-MABP) values were removed from the analysis for all gain, phase and autoregulation index (ARI) parameters. Gain in the low frequency band (LF) had the highest ICC, followed by phase LF and gain in the very low frequency band. No significant differences were found between analysis methods for gain parameters, but for phase and ARI parameters, significant differences between the analysis methods were found. Alternatively, the Spearman-Brown prediction formula indicated that prolongation of the measurement duration up to 35 minutes may be needed to achieve good reproducibility for some DCA parameters. We conclude that poor DCA reproducibility (ICC<0.4) can improve to good (ICC > 0.6) values when cases with low PSD-MABP are removed, and probably also when measurement duration is increased.
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Affiliation(s)
- Jan Willem Elting
- Department of Neurology, University Medical Center Groningen, Groningen, The Netherlands
- * E-mail:
| | - Marit L. Sanders
- Department of Geriatric Medicine, Radboudumc Alzheimer Centre and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ronney B. Panerai
- Department of Cardiovascular Sciences and Leicester Biomedical Research Centre in Cardiovascular Sciences, Glenfield Hospital, Leicester, United Kingdom
| | - Marcel Aries
- Department of Intensive Care, University of Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Edson Bor-Seng-Shu
- Department of Neurology, Hospital das Clinicas University of Sao Paulo, Sao Paulo, Brazil
| | - Alexander Caicedo
- Mathematics and Computer Science, Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Bogotá, Colombia
| | - Max Chacon
- Departemento de Ingeniería Informática, Universidad de Santiago de Chile, Santiago de Chile, Chile
| | - Erik D. Gommer
- Department of Clinical Neurophysiology, University of Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Sabine Van Huffel
- Department of Electronic Engineering, Stadius Center for Dynamical Systems, Signal Processing and Data Analytics, Katholieke Universiteit Leuven, Leuven, Belgium
| | - José L. Jara
- Departemento de Ingeniería Informática, Universidad de Santiago de Chile, Santiago de Chile, Chile
| | - Kyriaki Kostoglou
- Department of Electrical, Computer and Software Engineering, McGill University, Montreal, Canada
| | - Adam Mahdi
- Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Vasilis Z. Marmarelis
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, United States of America
| | | | - Martin Müller
- Department of Neurology, Luzerner Kantonsspital, Luzern, Switzerland
| | - Dragana Nikolic
- Institute of Sound and Vibration Research, University of Southampton, Southampton, United Kingdom
| | - Ricardo C. Nogueira
- Department of Neurology, Hospital das Clinicas University of Sao Paulo, Sao Paulo, Brazil
| | - Stephen J. Payne
- Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Corina Puppo
- Departamento de Emergencia, Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay
| | - Dae C. Shin
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, United States of America
| | - David M. Simpson
- Institute of Sound and Vibration Research, University of Southampton, Southampton, United Kingdom
| | - Takashi Tarumi
- The Institute for Exercise and Environmental Medicine, Presbyterian Hospital Dallas, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Bernardo Yelicich
- Departamento de Emergencia, Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay
| | - Rong Zhang
- The Institute for Exercise and Environmental Medicine, Presbyterian Hospital Dallas, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
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Robertson AD, Atwi S, Kostoglou K, Verhoeff NPLG, Oh PI, Mitsis GD, Marzolini S, MacIntosh BJ. Cerebrovascular Pulsatility During Rest and Exercise Reflects Hemodynamic Impairment in Stroke and Cerebral Small Vessel Disease. Ultrasound Med Biol 2019; 45:3116-3127. [PMID: 31570171 DOI: 10.1016/j.ultrasmedbio.2019.08.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 07/24/2019] [Accepted: 08/28/2019] [Indexed: 06/10/2023]
Abstract
Although aerobic exercise is recommended as a core component of stroke rehabilitation, knowledge of acute cerebrovascular responses in patients is limited. This study tested the hypothesis that older adults with chronic stroke or cerebral small vessel disease (SVD) exhibit a greater increase in pulsatile hemodynamics during exercise compared with young and age-matched healthy adults. Middle cerebral artery blood flow velocity was acquired during 20 min of moderate intensity cycling in 51 participants from four groups (young, old, SVD and stroke). During rest, only the stroke group had a higher pulsatility index (PI) compared with the young group (1.02 ± 0.17 vs 0.83 ± 0.13; p = 0.038). During exercise, however, the SVD group exhibited a larger increase in PI (68 ± 20% relative to rest) than the young (47 ± 19%), old (45 ± 17%) and stroke (40 ± 25%) groups (p < 0.05, for each). The stress of aerobic exercise may reveal arterial dysfunction associated with latent and overt cerebrovascular disease.
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Affiliation(s)
- Andrew D Robertson
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Ottawa, Ontario, Canada; Hurvitz Brain Sciences Program, Sunnybrook Research Institute, University of Toronto, Toronto, Ontario, Canada.
| | - Sarah Atwi
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Ottawa, Ontario, Canada; Hurvitz Brain Sciences Program, Sunnybrook Research Institute, University of Toronto, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Kyriaki Kostoglou
- Department of Electrical, Computer and Software Engineering, McGill University, Montreal, Quebec, Canada
| | - Nicolaas Paul L G Verhoeff
- Department of Psychiatry, Division of Geriatric Psychiatry, University of Toronto, Toronto, Ontario, Canada; Sam and Ida Ross Memory Disorders Clinic, Baycrest Health Sciences, Toronto, Ontario, Canada
| | - Paul I Oh
- Toronto Rehab, University Health Network, Toronto Ontario, Canada; Peter Munk Cardiac Centre, University of Toronto, Toronto, Ontario, Canada
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, Quebec, Canada
| | - Susan Marzolini
- Toronto Rehab, University Health Network, Toronto Ontario, Canada
| | - Bradley J MacIntosh
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Ottawa, Ontario, Canada; Hurvitz Brain Sciences Program, Sunnybrook Research Institute, University of Toronto, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
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31
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Ghosh A, Dal Maso F, Roig M, Mitsis GD, Boudrias MH. Unfolding the Effects of Acute Cardiovascular Exercise on Neural Correlates of Motor Learning Using Convolutional Neural Networks. Front Neurosci 2019; 13:1215. [PMID: 31798403 PMCID: PMC6868001 DOI: 10.3389/fnins.2019.01215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 10/28/2019] [Indexed: 12/19/2022] Open
Abstract
Cardiovascular exercise is known to promote the consolidation of newly acquired motor skills. Previous studies seeking to understand the neural correlates underlying motor memory consolidation that is modulated by exercise, have relied so far on using traditional statistical approaches for a priori selected features from neuroimaging data, including EEG. With recent advances in machine learning, data-driven techniques such as deep learning have shown great potential for EEG data decoding for brain-computer interfaces, but have not been explored in the context of exercise. Here, we present a novel Convolutional Neural Network (CNN)-based pipeline for analysis of EEG data to study the brain areas and spectral EEG measures modulated by exercise. To the best of our knowledge, this work is the first one to demonstrate the ability of CNNs to be trained in a limited sample size setting. Our approach revealed discriminative spectral features within a refined frequency band (27–29 Hz) as compared to the wider beta bandwidth (15–30 Hz), which is commonly used in data analyses, as well as corresponding brain regions that were modulated by exercise. These results indicate the presence of finer EEG spectral features that could have been overlooked using conventional hypothesis-driven statistical approaches. Our study thus demonstrates the feasibility of using deep network architectures for neuroimaging analysis, even in small-scale studies, to identify robust brain biomarkers and investigate neuroscience-based questions.
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Affiliation(s)
- Arna Ghosh
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
| | - Fabien Dal Maso
- École de Kinéiologie et des Sciences de l'Activité Physique, Université de Montréal, Montreal, QC, Canada
| | - Marc Roig
- School of Physical and Occupational Therapy, McGill University, Montreal, QC, Canada.,Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, QC, Canada
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, QC, Canada
| | - Marie-Hélène Boudrias
- School of Physical and Occupational Therapy, McGill University, Montreal, QC, Canada.,Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montreal, QC, Canada
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32
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Savva AD, Kassinopoulos M, Smyrnis N, Matsopoulos GK, Mitsis GD. Effects of motion related outliers in dynamic functional connectivity using the sliding window method. J Neurosci Methods 2019; 330:108519. [PMID: 31730872 DOI: 10.1016/j.jneumeth.2019.108519] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 11/01/2019] [Accepted: 11/11/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND It has been suggested that the use of window functions, other than the rectangular, in the sliding window method, may be beneficial for reducing the effects of motion-related outliers in the time-series, when assessing dynamic functional connectivity (dFC) in resting-state fMRI (rs-fMRI). METHODOLOGY Ten window functions for a wide range of window lengths (20-150 s) combined with Pearson and Kendall correlation metrics, were investigated. One hundred high quality rs-fMRI datasets from healthy controls, were used to systematically assess the effect of varying the window function and length on dFC assessment. To this end, two approaches were implemented: a) simulated outliers were added to the experimental data and b) the experimental data were divided into low and high motion subgroups. RESULTS The presence of experimental motion-noise tended to inflate the number of dynamic connections for longer (≥100 s) wide-shaped windows, while shorter (20-30 s) narrow-shaped windows exhibited increased sensitivity in the presence of simulated outliers. Moreover, window sizes from 60 s to 90 s were mildly affected by motion-related effects. In most cases, the number of dynamic connections increased, and gradually lower frequencies were captured, with an increasing window size. CONCLUSIONS Subject motion considerably affects the obtained dFC patterns; thus, it is preferable to perform motion artefact removal in the pre-processing stage rather than using alternative window functions to mitigate their effects. Provided that motion-noise is not excessive, the choice of a rectangular window is adequate. Finally, low frequency oscillations in functional connectivity seem to play an important role in the context of dFC assessment.
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Affiliation(s)
- Antonis D Savva
- School of Electrical and Computer Engineering, National Technical University of Athens, Athens, Greece.
| | - Michalis Kassinopoulos
- Graduate Program in Biological and Biomedical Engineering, McGill University, Montreal, QC, Canada
| | - Nikolaos Smyrnis
- Laboratory of Cognitive Neuroscience, University Mental Health Research Institute, Athens, Greece; Psychiatry Department, Medical School, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - George K Matsopoulos
- School of Electrical and Computer Engineering, National Technical University of Athens, Athens, Greece
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, QC, Canada
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33
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Kassinopoulos M, Mitsis GD. Identification of physiological response functions to correct for fluctuations in resting-state fMRI related to heart rate and respiration. Neuroimage 2019; 202:116150. [PMID: 31487547 DOI: 10.1016/j.neuroimage.2019.116150] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/30/2019] [Accepted: 08/30/2019] [Indexed: 12/31/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) is widely viewed as the gold standard for studying brain function due to its high spatial resolution and non-invasive nature. However, it is well established that changes in breathing patterns and heart rate strongly influence the blood oxygen-level dependent (BOLD) fMRI signal and this, in turn, can have considerable effects on fMRI studies, particularly resting-state studies. The dynamic effects of physiological processes are often quantified by using convolution models along with simultaneously recorded physiological data. In this context, physiological response function (PRF) curves (cardiac and respiratory response functions), which are convolved with the corresponding physiological fluctuations, are commonly employed. While it has often been suggested that the PRF curves may be region- or subject-specific, it is still an open question whether this is the case. In the present study, we propose a novel framework for the robust estimation of PRF curves and use this framework to rigorously examine the implications of using population-, subject-, session- and scan-specific PRF curves. The proposed framework was tested on resting-state fMRI and physiological data from the Human Connectome Project. Our results suggest that PRF curves vary significantly across subjects and, to a lesser extent, across sessions from the same subject. These differences can be partly attributed to physiological variables such as the mean and variance of the heart rate during the scan. The proposed methodological framework can be used to obtain robust scan-specific PRF curves from data records with duration longer than 5 min, exhibiting significantly improved performance compared to previously defined canonical cardiac and respiration response functions. Besides removing physiological confounds from the BOLD signal, accurate modeling of subject- (or session-/scan-) specific PRF curves is of importance in studies that involve populations with altered vascular responses, such as aging subjects.
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Affiliation(s)
- Michalis Kassinopoulos
- Graduate Program in Biological and Biomedical Engineering, McGill University, Montreal, QC, Canada
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, QC, Canada.
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Xifra-Porxas A, Niso G, Larivière S, Kassinopoulos M, Baillet S, Mitsis GD, Boudrias MH. Older adults exhibit a more pronounced modulation of beta oscillations when performing sustained and dynamic handgrips. Neuroimage 2019; 201:116037. [PMID: 31330245 DOI: 10.1016/j.neuroimage.2019.116037] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 07/12/2019] [Accepted: 07/19/2019] [Indexed: 11/20/2022] Open
Abstract
Muscle contractions are associated with a decrease in beta oscillatory activity, known as movement-related beta desynchronization (MRBD). Older adults exhibit a MRBD of greater amplitude compared to their younger counterparts, even though their beta power remains higher both at rest and during muscle contractions. Further, a modulation in MRBD has been observed during sustained and dynamic pinch contractions, whereby beta activity during periods of steady contraction following a dynamic contraction is elevated. However, how the modulation of MRBD is affected by aging has remained an open question. In the present work, we investigated the effect of aging on the modulation of beta oscillations and their putative link with motor performance. We collected magnetoencephalography (MEG) data from younger and older adults during a resting-state period and motor handgrip paradigms, which included sustained and dynamic contractions, to quantify spontaneous and motor-related beta oscillatory activity. Beta power at rest was found to be significantly increased in the motor cortex of older adults. During dynamic hand contractions, MRBD was more pronounced in older participants in frontal, premotor and motor brain regions. These brain areas also exhibited age-related decreases in cortical thickness; however, the magnitude of MRBD and cortical thickness were not found to be associated after controlling for age. During sustained hand contractions, MRBD exhibited a decrease in magnitude compared to dynamic contraction periods in both groups and did not show age-related differences. This suggests that the amplitude change in MRBD between dynamic and sustained contractions is larger in older compared to younger adults. We further probed for a relationship between beta oscillations and motor behaviour and found that greater MRBD in primary motor cortices was related to degraded motor performance beyond age, but our results suggested that age-related differences in beta oscillations were not predictive of motor performance.
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Affiliation(s)
- Alba Xifra-Porxas
- Graduate Program in Biological and Biomedical Engineering, McGill University, Montréal, Canada; Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montréal, Canada
| | - Guiomar Niso
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montréal, Canada; Center for Biomedical Technology, Universidad Politécnica de Madrid, Madrid, Spain; Biomedical Image Technologies, Universidad Politécnica de Madrid and CIBER-BBN, Madrid, Spain
| | - Sara Larivière
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montréal, Canada; Integrated Program in Neuroscience, McGill University, Montréal, Canada
| | - Michalis Kassinopoulos
- Graduate Program in Biological and Biomedical Engineering, McGill University, Montréal, Canada
| | - Sylvain Baillet
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montréal, Canada
| | | | - Marie-Hélène Boudrias
- Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montréal, Canada; School of Physical and Occupational Therapy, McGill University, Montréal, Canada.
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35
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Sanders ML, Elting JWJ, Panerai RB, Aries M, Bor-Seng-Shu E, Caicedo A, Chacon M, Gommer ED, Van Huffel S, Jara JL, Kostoglou K, Mahdi A, Marmarelis VZ, Mitsis GD, Müller M, Nikolic D, Nogueira RC, Payne SJ, Puppo C, Shin DC, Simpson DM, Tarumi T, Yelicich B, Zhang R, Claassen JAHR. Dynamic Cerebral Autoregulation Reproducibility Is Affected by Physiological Variability. Front Physiol 2019; 10:865. [PMID: 31354518 PMCID: PMC6634255 DOI: 10.3389/fphys.2019.00865] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 06/20/2019] [Indexed: 11/24/2022] Open
Abstract
Parameters describing dynamic cerebral autoregulation (DCA) have limited reproducibility. In an international, multi-center study, we evaluated the influence of multiple analytical methods on the reproducibility of DCA. Fourteen participating centers analyzed repeated measurements from 75 healthy subjects, consisting of 5 min of spontaneous fluctuations in blood pressure and cerebral blood flow velocity signals, based on their usual methods of analysis. DCA methods were grouped into three broad categories, depending on output types: (1) transfer function analysis (TFA); (2) autoregulation index (ARI); and (3) correlation coefficient. Only TFA gain in the low frequency (LF) band showed good reproducibility in approximately half of the estimates of gain, defined as an intraclass correlation coefficient (ICC) of >0.6. None of the other DCA metrics had good reproducibility. For TFA-like and ARI-like methods, ICCs were lower than values obtained with surrogate data (p < 0.05). For TFA-like methods, ICCs were lower for the very LF band (gain 0.38 ± 0.057, phase 0.17 ± 0.13) than for LF band (gain 0.59 ± 0.078, phase 0.39 ± 0.11, p ≤ 0.001 for both gain and phase). For ARI-like methods, the mean ICC was 0.30 ± 0.12 and for the correlation methods 0.24 ± 0.23. Based on comparisons with ICC estimates obtained from surrogate data, we conclude that physiological variability or non-stationarity is likely to be the main reason for the poor reproducibility of DCA parameters.
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Affiliation(s)
- Marit L Sanders
- Department of Geriatric Medicine, Radboudumc Alzheimer Center, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
| | - Jan Willem J Elting
- Department of Neurology, University Medical Center Groningen, Groningen, Netherlands
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, NIHR Leicester Biomedical Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Marcel Aries
- Department of Intensive Care, University of Maastricht, Maastricht University Medical Center, Maastricht, Netherlands
| | - Edson Bor-Seng-Shu
- Department of Neurology, Faculty of Medicine, Hospital das Clinicas University of São Paulo, São Paulo, Brazil
| | - Alexander Caicedo
- Department of Applied Mathematics and Computer Science, Faculty of Natural Sciences and Mathematics, Universidad del Rosario, Bogotá, Colombia
| | - Max Chacon
- Department of Engineering Informatics, Institute of Biomedical Engineering, University of Santiago, Santiago, Chile
| | - Erik D Gommer
- Department of Clinical Neurophysiology, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Sabine Van Huffel
- Department of Electronic Engineering (ESAT), Stadius Center for Dynamical Systems, Signal Processing and Data Analytics, Katholieke Universiteit Leuven, Leuven, Belgium.,Interuniversity Microelectronics Centre, Leuven, Belgium
| | - José L Jara
- Department of Engineering Informatics, Institute of Biomedical Engineering, University of Santiago, Santiago, Chile
| | - Kyriaki Kostoglou
- Department of Electrical, Computer and Software Engineering, McGill University, Montreal, QC, Canada
| | - Adam Mahdi
- Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Vasilis Z Marmarelis
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, QC, Canada
| | - Martin Müller
- Department of Neurology, Luzerner Kantonsspital, Luzern, Switzerland
| | - Dragana Nikolic
- Faculty of Engineering and the Environment, Institute of Sound and Vibration Research, University of Southampton, Southampton, United Kingdom
| | - Ricardo C Nogueira
- Department of Neurology, Faculty of Medicine, Hospital das Clinicas University of São Paulo, São Paulo, Brazil
| | - Stephen J Payne
- Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Corina Puppo
- Departamento de Emergencia, Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay
| | - Dae C Shin
- Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, United States
| | - David M Simpson
- Faculty of Engineering and the Environment, Institute of Sound and Vibration Research, University of Southampton, Southampton, United Kingdom
| | - Takashi Tarumi
- Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Bernardo Yelicich
- Departamento de Emergencia, Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay
| | - Rong Zhang
- Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Jurgen A H R Claassen
- Department of Geriatric Medicine, Radboudumc Alzheimer Center, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
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Prokopiou PC, Mitsis GD. Modeling of the BOLD signal using event-related simultaneous EEG-fMRI and convolutional sparse coding analysis. Annu Int Conf IEEE Eng Med Biol Soc 2019; 2019:181-184. [PMID: 31945873 DOI: 10.1109/embc.2019.8857311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In this work, we employ simultaneous EEG-fMRI data acquired during a visually-guided attention task along with convolutional sparse coding (CSC) analysis to extract transient events from the EEG. Subsequently, we use these events in a standard voxel-wise fMRI analysis and compare the resultant activation maps with maps obtained using the subjects' response time (RT) in detection of visual target stimuli. We also employ FIR models to obtain HRF estimates using the detected CSC events. Our results show concordance between the resultant activation maps and consistent HRF shapes for most of the subjects, suggesting that CSC can be used as a tool for the detection of reliable events in the EEG.
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Savva AD, Mitsis GD, Matsopoulos GK. Assessment of dynamic functional connectivity in resting-state fMRI using the sliding window technique. Brain Behav 2019; 9:e01255. [PMID: 30884215 PMCID: PMC6456784 DOI: 10.1002/brb3.1255] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 02/01/2019] [Accepted: 02/15/2019] [Indexed: 01/01/2023] Open
Abstract
INTRODUCTION Recent studies related to assessing functional connectivity (FC) in resting-state functional magnetic resonance imaging have revealed that the resulting connectivity patterns exhibit considerable fluctuations (dynamic FC [dFC]). A widely applied method for quantifying dFC is the sliding window technique. According to this method, the data are divided into segments with the same length (window size) and a correlation metric is employed to assess the connectivity within these segments, whereby the window size is often empirically chosen. METHODS In this study, we rigorously investigate the assessment of dFC using the sliding window approach. Specifically, we perform a detailed comparison between different correlation metrics, including Pearson, Spearman and Kendall correlation, Pearson and Spearman partial correlation, Mutual Information (MI), Variation of Information (VI), Kullback-Leibler divergence, Multiplication of Temporal Derivatives and Inverse Covariance. RESULTS Using test-retest datasets, we show that MI and VI yielded the most consistent results by achieving high reliability with respect to dFC estimates for different window sizes. Subsequent hypothesis testing, based on multivariate phase randomization surrogate data generation, allowed the identification of dynamic connections between the posterior cingulate cortex and regions in the frontal lobe and inferior parietal lobes, which were overall in agreement with previous studies. CONCLUSIONS In the case of MI and VI, a window size of at least 120 s was found to be necessary for detecting dFC for some of the previously identified dynamically connected regions.
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Affiliation(s)
- Antonis D Savva
- School of Electrical and Computer Engineering, National Technical University of Athens, Athens, Greece
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, Quebec, Canada
| | - George K Matsopoulos
- School of Electrical and Computer Engineering, National Technical University of Athens, Athens, Greece
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Anastasiadou MN, Christodoulakis M, Papathanasiou ES, Papacostas SS, Hadjipapas A, Mitsis GD. Graph Theoretical Characteristics of EEG-Based Functional Brain Networks in Patients With Epilepsy: The Effect of Reference Choice and Volume Conduction. Front Neurosci 2019; 13:221. [PMID: 30949021 PMCID: PMC6436604 DOI: 10.3389/fnins.2019.00221] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/26/2019] [Indexed: 12/22/2022] Open
Abstract
It is well-established that both volume conduction and the choice of recording reference (montage) affect the correlation measures obtained from scalp EEG, both in the time and frequency domains. As a result, a number of correlation measures have been proposed aiming to reduce these effects. In our previous work, we have showed that scalp-EEG based functional brain networks in patients with epilepsy exhibit clear periodic patterns at different time scales and that these patterns are strongly correlated to seizure onset, particularly at shorter time scales (around 3 and 5 h), which has important clinical implications. In the present work, we use the same long-duration clinical scalp EEG data (multiple days) to investigate the extent to which the aforementioned results are affected by the choice of reference choice and correlation measure, by considering several widely used montages as well as correlation metrics that are differentially sensitive to the effects of volume conduction. Specifically, we compare two standard and commonly used linear correlation measures, cross-correlation in the time domain, and coherence in the frequency domain, with measures that account for zero-lag correlations: corrected cross-correlation, imaginary coherence, phase lag index, and weighted phase lag index. We show that the graphs constructed with corrected cross-correlation and WPLI are more stable across different choices of reference. Also, we demonstrate that all the examined correlation measures revealed similar periodic patterns in the obtained graph measures when the bipolar and common reference (Cz) montage were used. This includes circadian-related periodicities (e.g., a clear increase in connectivity during sleep periods as compared to awake periods), as well as periodicities at shorter time scales (around 3 and 5 h). On the other hand, these results were affected to a large degree when the average reference montage was used in combination with standard cross-correlation, coherence, imaginary coherence, and PLI, which is likely due to the low number of electrodes and inadequate electrode coverage of the scalp. Finally, we demonstrate that the correlation between seizure onset and the brain network periodicities is preserved when corrected cross-correlation and WPLI were used for all the examined montages. This suggests that, even in the standard clinical setting of EEG recording in epilepsy where only a limited number of scalp EEG measurements are available, graph-theoretic quantification of periodic patterns using appropriate montage, and correlation measures corrected for volume conduction provides useful insights into seizure onset.
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Affiliation(s)
- Maria N Anastasiadou
- KIOS Research and Innovation Centre of Excellence, Faculty of Engineering, University of Cyprus, Nicosia, Cyprus
| | - Manolis Christodoulakis
- KIOS Research and Innovation Centre of Excellence, Faculty of Engineering, University of Cyprus, Nicosia, Cyprus
| | - Eleftherios S Papathanasiou
- Laboratory of Clinical Neurophysiology, Clinic B, Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Savvas S Papacostas
- Laboratory of Clinical Neurophysiology, Clinic B, Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | | | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, QC, Canada.,Department of Electrical and Computer Engineering, KIOS Research Center, University of Cyprus, Nicosia, Cyprus
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Larivière S, Xifra-Porxas A, Kassinopoulos M, Niso G, Baillet S, Mitsis GD, Boudrias MH. Functional and effective reorganization of the aging brain during unimanual and bimanual hand movements. Hum Brain Mapp 2019; 40:3027-3040. [PMID: 30866155 DOI: 10.1002/hbm.24578] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Revised: 02/20/2019] [Accepted: 03/04/2019] [Indexed: 02/03/2023] Open
Abstract
Motor performance decline observed during aging is linked to changes in brain structure and function, however, the precise neural reorganization associated with these changes remains largely unknown. We investigated the neurophysiological correlates of this reorganization by quantifying functional and effective brain network connectivity in elderly individuals (n = 11; mean age = 67.5 years), compared to young adults (n = 12; mean age = 23.7 years), while they performed visually-guided unimanual and bimanual handgrips inside the magnetoencephalography (MEG) scanner. Through a combination of principal component analysis and Granger causality, we observed age-related increases in functional and effective connectivity in whole-brain, task-related motor networks. Specifically, elderly individuals demonstrated (i) greater information flow from contralateral parietal and ipsilateral secondary motor regions to the left primary motor cortex during the unimanual task and (ii) decreased interhemispheric temporo-frontal communication during the bimanual task. Maintenance of motor performance and task accuracy in elderly was achieved by hyperactivation of the task-specific motor networks, reflecting a possible mechanism by which the aging brain recruits additional resources to counteract known myelo- and cytoarchitectural changes. Furthermore, resting-state sessions acquired before and after each motor task revealed that both older and younger adults maintain the capacity to adapt to task demands via network-wide increases in functional connectivity. Collectively, our study consolidates functional connectivity and directionality of information flow in systems-level cortical networks during aging and furthers our understanding of neuronal flexibility in motor processes.
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Affiliation(s)
- Sara Larivière
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montréal, Québec, Canada.,Department of Neurology and Neurosurgery, McGill University, Montréal, Québec, Canada
| | - Alba Xifra-Porxas
- Department of Biological and Biomedical Engineering, McGill University, Montréal, Québec, Canada
| | - Michalis Kassinopoulos
- Department of Biological and Biomedical Engineering, McGill University, Montréal, Québec, Canada
| | - Guiomar Niso
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montréal, Québec, Canada.,Center for Biomedical Technology, Technical University of Madrid, Madrid, Spain.,Biomedical Image Technologies, Technical University of Madrid and CIBER-BBN, Madrid, Spain
| | - Sylvain Baillet
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montréal, Québec, Canada.,Department of Neurology and Neurosurgery, McGill University, Montréal, Québec, Canada
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montréal, Québec, Canada
| | - Marie-Hélène Boudrias
- School of Physical and Occupational Therapy, McGill University, Montréal, Québec, Canada.,Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montréal, Québec, Canada
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40
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Kostoglou K, Robertson AD, MacIntosh BJ, Mitsis GD. A Novel Framework for Estimating Time-Varying Multivariate Autoregressive Models and Application to Cardiovascular Responses to Acute Exercise. IEEE Trans Biomed Eng 2019; 66:3257-3266. [PMID: 30843796 DOI: 10.1109/tbme.2019.2903012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE We present a novel modeling framework for identifying time-varying (TV) couplings between time-series of biomedical relevance. METHODS The proposed methodology is based on multivariate autoregressive (MVAR) models, which have been extensively used to study couplings between biosignals. Contrary to the standard estimation methods that assume time-invariant relationships, we propose a modified recursive Kalman filter (KF) to track changes in the model parameters. We perform model order selection and hyperparameter optimization simultaneously using Genetic Algorithms, greatly improving accuracy and computation time. In addition, we address the effect of residual heteroscedasticity, possibly associated with event-related changes or phase transitions during a given experimental protocol, on the TV-MVAR coupling measures by using Generalized Autoregressive Conditional Heteroskedasticity (GARCH) models to fit the TV-MVAR residuals. RESULTS Using simulated data, we show that the proposed framework yields more accurate parameter estimates compared to the conventional KF, particularly when the true system parameters exhibit different rate of variations over time. Furthermore, by accounting for heteroskedasticity, we obtain more accurate estimates of the strength and directionality of the underlying couplings. We also use our approach to investigate TV hemodynamic interactions during exercise in young and old healthy adults, as well as individuals with chronic stroke. We extract TV coupling patterns that reflect well known exercise-induced effects on the underlying regulatory mechanisms with excellent time resolution. CONCLUSION AND SIGNIFICANCE The proposed modeling framework can be used to efficiently quantify TV couplings between biosignals. It is fully automated and does not require prior knowledge of the system TV characteristics.
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Sanders ML, Claassen JAHR, Aries M, Bor-Seng-Shu E, Caicedo A, Chacon M, Gommer ED, Van Huffel S, Jara JL, Kostoglou K, Mahdi A, Marmarelis VZ, Mitsis GD, Müller M, Nikolic D, Nogueira RC, Payne SJ, Puppo C, Shin DC, Simpson DM, Tarumi T, Yelicich B, Zhang R, Panerai RB, Elting JWJ. Reproducibility of dynamic cerebral autoregulation parameters: a multi-centre, multi-method study. Physiol Meas 2018; 39:125002. [PMID: 30523976 DOI: 10.1088/1361-6579/aae9fd] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
OBJECTIVE Different methods to calculate dynamic cerebral autoregulation (dCA) parameters are available. However, most of these methods demonstrate poor reproducibility that limit their reliability for clinical use. Inter-centre differences in study protocols, modelling approaches and default parameter settings have all led to a lack of standardisation and comparability between studies. We evaluated reproducibility of dCA parameters by assessing systematic errors in surrogate data resulting from different modelling techniques. APPROACH Fourteen centres analysed 22 datasets consisting of two repeated physiological blood pressure measurements with surrogate cerebral blood flow velocity signals, generated using Tiecks curves (autoregulation index, ARI 0-9) and added noise. For reproducibility, dCA methods were grouped in three broad categories: 1. Transfer function analysis (TFA)-like output; 2. ARI-like output; 3. Correlation coefficient-like output. For all methods, reproducibility was determined by one-way intraclass correlation coefficient analysis (ICC). MAIN RESULTS For TFA-like methods the mean (SD; [range]) ICC gain was 0.71 (0.10; [0.49-0.86]) and 0.80 (0.17; [0.36-0.94]) for VLF and LF (p = 0.003) respectively. For phase, ICC values were 0.53 (0.21; [0.09-0.80]) for VLF, and 0.92 (0.13; [0.44-1.00]) for LF (p < 0.001). Finally, ICC for ARI-like methods was equal to 0.84 (0.19; [0.41-0.94]), and for correlation-like methods, ICC was 0.21 (0.21; [0.056-0.35]). SIGNIFICANCE When applied to realistic surrogate data, free from the additional exogenous influences of physiological variability on cerebral blood flow, most methods of dCA modelling showed ICC values considerably higher than what has been reported for physiological data. This finding suggests that the poor reproducibility reported by previous studies may be mainly due to the inherent physiological variability of cerebral blood flow regulatory mechanisms rather than related to (stationary) random noise and the signal analysis methods.
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Affiliation(s)
- Marit L Sanders
- Department of Geriatric Medicine, Radboudumc Alzheimer Centre and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
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Prokopiou PC, Pattinson KTS, Wise RG, Mitsis GD. Modeling of dynamic cerebrovascular reactivity to spontaneous and externally induced CO 2 fluctuations in the human brain using BOLD-fMRI. Neuroimage 2018; 186:533-548. [PMID: 30423427 DOI: 10.1016/j.neuroimage.2018.10.084] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/09/2018] [Accepted: 10/31/2018] [Indexed: 11/30/2022] Open
Abstract
In this work, we investigate the regional characteristics of the dynamic interactions between arterial CO2 and BOLD (dynamic cerebrovascular reactivity - dCVR) during normal breathing and hypercapnic, externally induced step CO2 challenges. To obtain dCVR curves at each voxel, we use a custom set of basis functions based on the Laguerre and gamma basis sets. This allows us to obtain robust dCVR estimates both in larger regions of interest (ROIs), as well as in individual voxels. We also implement classification schemes to identify brain regions with similar dCVR characteristics. Our results reveal considerable variability of dCVR across different brain regions, as well as during different experimental conditions (normal breathing and hypercapnic challenges), suggesting a differential response of cerebral vasculature to spontaneous CO2 fluctuations and larger, externally induced CO2 changes that are possibly associated with the underlying differences in mean arterial CO2 levels. The clustering results suggest that anatomically distinct brain regions are characterized by different dCVR curves that in some cases do not exhibit the standard, positive valued curves that have been previously reported. They also reveal a consistent set of dCVR cluster shapes for resting and forcing conditions, which exhibit different distribution patterns across brain voxels.
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Affiliation(s)
- Prokopis C Prokopiou
- Integrated Program in Neuroscience, McGill University, Montreal Neurological Institude, H3A 2B4, QC, Canada
| | - Kyle T S Pattinson
- Nuffield Department of Anaesthetics, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - Richard G Wise
- CUBRIC, School of Psychology, University of Cardiff, CF10 3AT, UK
| | - Georgios D Mitsis
- Department of Bioengineering, McGill Univesity, Montreal, QC, H3A 0C3, Canada; Integrated Program in Neuroscience, McGill University, Montreal Neurological Institude, H3A 2B4, QC, Canada.
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Kostoglou K, Schondorf R, Benoit J, Balegh S, Mitsis GD. Prediction of the Time to Syncope Occurrence in Patients Diagnosed with Vasovagal Syncope. Acta Neurochir Suppl 2018; 126:313-316. [PMID: 29492581 DOI: 10.1007/978-3-319-65798-1_61] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE In this study we aimed to predict the time to syncope occurrence (TSO) in patients with vasovagal syncope (VVS), solely based on measurements recorded during the supine position of the head-up tilt (HUT) testing protocol. METHODS We extracted various time and frequency domain features related to morphological aspects of arterial blood pressure (ABP) and the electrocardiogram (ECG) raw signals as well as to dynamic interactions between beat-to-beat ABP, heart rate, and cerebral blood flow velocity. From these we identified the most predictive features related to TSO. RESULTS Specifically, when no orthostatic stress is involved, TSO in VVS patients can be predicted with high accuracy from a set of only five ECG features.
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Affiliation(s)
- Kyriaki Kostoglou
- Department of Electrical and Computer Engineering, McGill University, Montreal, QC, Canada
| | - Ronald Schondorf
- Department of Neurology, McGill University, Montreal, QC, Canada
| | - Julie Benoit
- Department of Neurology, McGill University, Montreal, QC, Canada
| | - Saharnaz Balegh
- Department of Neurology, McGill University, Montreal, QC, Canada
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montreal, QC, Canada.
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Patmanidis S, Charalampidis AC, Kordonis I, Mitsis GD, Papavassilopoulos GP. Tumor growth modeling: Parameter estimation with Maximum Likelihood methods. Comput Methods Programs Biomed 2018; 160:1-10. [PMID: 29728236 DOI: 10.1016/j.cmpb.2018.03.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 02/01/2018] [Accepted: 03/20/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND & OBJECTIVE In this work, we focus on estimating the parameters of the widely used Gompertz tumor growth model, based on measurements of the tumor's volume. Being able to accurately describe the dynamics of tumor growth on an individual basis is very important both for growth prediction and designing personalized, optimal therapy schemes (e.g. when using model predictive control). METHODS Our analysis aims to compute both the growth rate and the carrying capacity of the Gompertz function, along with the characteristics of the additive Gaussian process and measurement noise of the system. Three methods based on Maximum Likelihood estimation are proposed. The first utilizes an assumption regarding the measurement noise that simplifies the problem, the second combines the Extended Kalman Filter and Maximum Likelihood estimation, and the third is a nonstandard exact form of Maximum Likelihood estimation, where numerical integration is used to approximate the likelihood of the measurements, along with a novel way to reduce the required computations. RESULTS Synthetic data were used in order to perform extensive simulations aiming to compare the methods' effectiveness, with respect to the accuracy of the estimation. The proposed methods are able to estimate the growth dynamics, even when the noise characteristics are not estimated accurately. Another very important finding is that the methods perform best in the case that corresponds to the problem needed to be solved when dealing with experimental data. CONCLUSION Using nonstandard, problem specific techniques can improve the estimation accuracy and best exploit the available data.
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Affiliation(s)
- Spyridon Patmanidis
- School of Electrical and Computer Engineering, National Technical University of Athens, Iroon Polytechneiou 9, Zografou, Athens 15780, Greece.
| | - Alexandros C Charalampidis
- Department of Electrical Engineering and Computer Science, Technische Universität Berlin, Control Systems Group, Einsteinufer 17, Berlin D-10587, Germany; CentraleSupélec, Automatic Control Group - IETR, Avenue de la Boulaie, Cesson-Sévigné 35576 , France.
| | - Ioannis Kordonis
- CentraleSupélec, Automatic Control Group - IETR, Avenue de la Boulaie, Cesson-Sévigné 35576 , France.
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, 817 Sherbrooke Ave W, MacDonald Engineering Building 270, Montréal, QC H3A 0C3, Canada.
| | - George P Papavassilopoulos
- School of Electrical and Computer Engineering, National Technical University of Athens, Iroon Polytechneiou 9, Zografou, Athens 15780, Greece.
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Xifra-Porxas A, Kostoglou K, Lariviere S, Niso G, Kassinopoulos M, Boudrias MH, Mitsis GD. Identification of Time-Varying Cortico-cortical and Cortico-Muscular Coherence during Motor Tasks with Multivariate Autoregressive Models. Annu Int Conf IEEE Eng Med Biol Soc 2018; 2018:1024-1021. [PMID: 30440565 DOI: 10.1109/embc.2018.8512475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Neural populations coordinate at fast subsecond time-scales during rest and task execution. As a result, functional brain connectivity assessed with different neuroimaging modalities (EEG, MEG, fMRI) may also change over different time scales. In addition to the more commonly used sliding window techniques, the General Linear Kalman Filter (GLFK) approach has been proposed to estimate time-varying brain connectivity. In the present work, we propose a modification of the GLFK approach to model timevarying connectivity. We also propose a systematic method to select the hyper-parameters of the model. We evaluate the performance of the method using MEG and EMG data collected from 12 young subjects performing two motor tasks (unimanual and bimanual hand grips), by quantifying time-varying cortico-cortical and corticomuscular coherence (CCC and CMC). The CMC results revealed patterns in accordance with earlier findings, as well as an improvement in both time and frequency resolution compared to sliding window approaches. These results suggest that the proposed methodology is able to unveil accurate time-varying connectivity patterns with an excellent time resolution.
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Nikolaou F, Orphanidou C, Murphy K, Wise RG, Mitsis GD. Investigation Of Interaction Between Physiological Signals And fMRI Dynamic Functional Connectivity Using Independent Component Analysis. Annu Int Conf IEEE Eng Med Biol Soc 2018; 2018:1019-1023. [PMID: 30440564 DOI: 10.1109/embc.2018.8512465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The blood oxygen level dependent (BOLD) fMRI signal is influenced not only by neuronal activity but also by fluctuations in physiological signals, including respiration, arterial CO2 and heart rate/ heart rate variability (HR/HRV). Even spontaneous physiological signal fluctuations have been shown to influence the BOLD fMRI signal in a regionally specific manner. Consequently, estimates of functional connectivity between different brain regions, performed when the subject is at rest, may be confounded by the effects of physiological signal fluctuations. In addition, resting functional connectivity has been shown to vary with respect to time (dynamic functional connectivity - DFC), with the sources of this variation not fully elucidated. The effect of physiological factors on dynamic (time-varying) resting-state functional connectivity has not been studied extensively, to our knowledge. In our previous study, we investigated the effect of heart rate (HR) and end-tidal CO2 (PETCO2) on the time-varying network degree of three well-described RSNs (DMN, SMN and Visual Network) using mask-based and seed-based analysis, and we identified brain-heart interactions which were more pronounced in specific frequency bands. Here, we extend this work, by estimating DFC and its corresponding network degree for the RSNs, employing a data-driven approach to extract the RSNs (low-and high-dimensional Independent Component Analysis (ICA)), which we subsequently correlate with the characteristics of simultaneously collected physiological signals. The results confirm that physiological signals have a modulatory effect on resting-state, fMRI-based DFC.
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Waltz X, Beaudin AE, Hanly PJ, Mitsis GD, Poulin MJ. Effects of continuous positive airway pressure and isocapnic-hypoxia on cerebral autoregulation in patients with obstructive sleep apnoea. J Physiol 2017; 594:7089-7104. [PMID: 27644162 DOI: 10.1113/jp272967] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 09/16/2016] [Indexed: 01/01/2023] Open
Abstract
KEY POINTS Altered cerebral autoregulation (CA) in obstructive sleep apnoea (OSA) patients may contribute to increased stroke risk in this population; the gold standard treatment for OSA is continuous positive airway pressure, which improves cerebrovascular regulation and may decrease the risk of stroke. Isocapnic-hypoxia impairs CA in healthy subjects, but it remains unknown in OSA whether impaired CA is further exacerbated by isocapnic-hypoxia and whether it is improved by treatment with continuous positive airway pressure. During normoxia, CA was altered in the more severe but not in the less severe OSA patients, while, in contrast, during isocapnic-hypoxia, CA was similar between groups and tended to improve in patients with more severe OSA compared to normoxia. From a clinical perspective, one month of continuous positive airway pressure treatment does not improve CA. From a physiological perspective, this study suggests that sympathetic overactivity may be responsible for altered CA in the more severe OSA patients. ABSTRACT Cerebral autoregulation (CA) impairment may contribute to the increased risk of stroke associated with obstructive sleep apnoea (OSA). It is unknown if impaired CA is further exacerbated by isocapnic-hypoxia and whether it is improved by treatment of OSA with continuous positive airway pressure (CPAP). CA was assessed during wakefulness in 53 OSA patients (50.3 ± 9.3 years) and 21 controls (49.8 ± 8.6 years) at baseline and following a minimum of 1 month of effective CPAP therapy (OSA patients, n = 40). Control participants (n = 21) performed a follow-up visit to control for time effects within OSA patients between baseline and the post-CPAP visit. Beat-by-beat middle cerebral artery blood flow velocity and mean arterial blood pressure (MBP), and breath-by-breath end-tidal partial pressure of CO2 (P ET ,CO2) were monitored. CA was determined during normoxia and isocapnic-hypoxia using transfer function (phase and gain) and coherence analysis (including multiple and partial coherence (using MBP and P ET ,CO2 as inputs)) in the very low frequency range (0.03-0.07 Hz). OSA patients were divided into two subgroups (less severe and more severe) based upon the median respiratory disturbance index (RDI). During normoxia, the more severe OSA patients (RDI 45.9 ± 10.3) exhibited altered CA compared to controls and the less severe OSA patients (RDI 24.5 ± 5.9). In contrast, during isocapnic-hypoxia, CA was similar between groups. CPAP had no effect on CA. In conclusion, CA is altered in the more severe OSA patients during normoxia but not during isocapnic-hypoxia and CPAP treatment does not impact CA.
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Affiliation(s)
- Xavier Waltz
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Andrew E Beaudin
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Patrick J Hanly
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Sleep Centre, Foothills Medical Centre, Calgary, AB, Canada
| | - Georgios D Mitsis
- Department of Bioengineering, McGill University, Montréal, Québec, Canada
| | - Marc J Poulin
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.,Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
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Prokopiou PC, Murphy K, Wise RG, Mitsis GD. Estimation of voxel-wise dynamic cerebrovascular reactivity curves from resting-state fMRI data. Annu Int Conf IEEE Eng Med Biol Soc 2017; 2016:1143-1146. [PMID: 28268528 DOI: 10.1109/embc.2016.7590906] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this work, we investigate the linear dynamic interactions between fluctuations in arterial CO2 that occur during normal breathing, and the BOLD fMRI signal. We cast this problem within a systems-theoretic framework, where we employ functional expansions for the estimation of the impulse responses in large regions of interest, as well as in individual voxels. We also implement classification schemes in order to identify different brain regions with similar cerebrovascular reactivity characteristics. Our results reveal that it is feasible to obtain reliable estimates of cerebrovascular reactivity curves from resting-state data and that these curves exhibit considerable variability across different brain regions that may be related to the underlying anatomy.
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Anastasiadou MN, Christodoulakis M, Papathanasiou ES, Papacostas SS, Mitsis GD. Unsupervised detection and removal of muscle artifacts from scalp EEG recordings using canonical correlation analysis, wavelets and random forests. Clin Neurophysiol 2017; 128:1755-1769. [PMID: 28778057 DOI: 10.1016/j.clinph.2017.06.247] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 05/19/2017] [Accepted: 06/20/2017] [Indexed: 11/15/2022]
Abstract
OBJECTIVE This paper proposes supervised and unsupervised algorithms for automatic muscle artifact detection and removal from long-term EEG recordings, which combine canonical correlation analysis (CCA) and wavelets with random forests (RF). METHODS The proposed algorithms first perform CCA and continuous wavelet transform of the canonical components to generate a number of features which include component autocorrelation values and wavelet coefficient magnitude values. A subset of the most important features is subsequently selected using RF and labelled observations (supervised case) or synthetic data constructed from the original observations (unsupervised case). The proposed algorithms are evaluated using realistic simulation data as well as 30min epochs of non-invasive EEG recordings obtained from ten patients with epilepsy. RESULTS We assessed the performance of the proposed algorithms using classification performance and goodness-of-fit values for noisy and noise-free signal windows. In the simulation study, where the ground truth was known, the proposed algorithms yielded almost perfect performance. In the case of experimental data, where expert marking was performed, the results suggest that both the supervised and unsupervised algorithm versions were able to remove artifacts without affecting noise-free channels considerably, outperforming standard CCA, independent component analysis (ICA) and Lagged Auto-Mutual Information Clustering (LAMIC). CONCLUSION The proposed algorithms achieved excellent performance for both simulation and experimental data. Importantly, for the first time to our knowledge, we were able to perform entirely unsupervised artifact removal, i.e. without using already marked noisy data segments, achieving performance that is comparable to the supervised case. SIGNIFICANCE Overall, the results suggest that the proposed algorithms yield significant future potential for improving EEG signal quality in research or clinical settings without the need for marking by expert neurophysiologists, EMG signal recording and user visual inspection.
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Affiliation(s)
- Maria N Anastasiadou
- McGill University, Department of Bioengineering, 817 Sherbrooke St. W., Macdonald Engineering Building, Room 270, Montreal, QC H3A 0C3, Canada
| | - Manolis Christodoulakis
- McGill University, Department of Bioengineering, 817 Sherbrooke St. W., Macdonald Engineering Building, Room 270, Montreal, QC H3A 0C3, Canada
| | - Eleftherios S Papathanasiou
- McGill University, Department of Bioengineering, 817 Sherbrooke St. W., Macdonald Engineering Building, Room 270, Montreal, QC H3A 0C3, Canada
| | - Savvas S Papacostas
- McGill University, Department of Bioengineering, 817 Sherbrooke St. W., Macdonald Engineering Building, Room 270, Montreal, QC H3A 0C3, Canada
| | - Georgios D Mitsis
- McGill University, Department of Bioengineering, 817 Sherbrooke St. W., Macdonald Engineering Building, Room 270, Montreal, QC H3A 0C3, Canada.
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Anastasiadou M, Hadjipapas A, Christodoulakis M, Papathanasiou ES, Papacostas SS, Mitsis GD. Epileptic seizure onset correlates with long term EEG functional brain network properties. Annu Int Conf IEEE Eng Med Biol Soc 2017; 2016:2822-2825. [PMID: 28268905 DOI: 10.1109/embc.2016.7591317] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We investigated the correlation of epileptic seizure onset times with long term EEG functional brain network properties. To do so, we constructed binary functional brain networks from long-term, multichannel electroencephalographic data recorded from nine patients with epilepsy. The corresponding network properties were quantified using the average network degree. It was found that the network degree (as well as other network properties such as the network efficiency and clustering coefficient) exhibited large fluctuations over time; however, it also exhibited specific periodic temporal structure over different time scales (1.5hr-24hr periods) that was consistent across subjects. We investigated the correlation of the phases of these network periodicities with the seizure onset by using circular statistics. The results showed that the instantaneous phases of the 3.5hr, 5.5hr, 12hr and 24hr network degree periodic components are not uniformly distributed, suggesting that functional network properties are related to seizure generation and occurrence.
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