101
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Malik SA, Mir AH. Discrete Multiplierless Implementation of Fractional Order Hindmarsh–Rose Model. IEEE TRANSACTIONS ON EMERGING TOPICS IN COMPUTATIONAL INTELLIGENCE 2021. [DOI: 10.1109/tetci.2020.2979462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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102
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Tzagarakis C, West S, Pellizzer G. Neural Encoding of the Reliability of Directional Information During the Preparation of Targeted Movements. Front Neurosci 2021; 15:679408. [PMID: 34504412 PMCID: PMC8421604 DOI: 10.3389/fnins.2021.679408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 07/23/2021] [Indexed: 11/18/2022] Open
Abstract
Visual information about the location of an upcoming target can be used to prepare an appropriate motor response and reduce its reaction time. Here, we investigated the brain mechanisms associated with the reliability of directional information used for motor preparation. We recorded brain activity using magnetoencephalography (MEG) during a delayed reaching task in which a visual cue provided valid information about the location of the upcoming target with 50, 75, or 100% reliability. We found that reaction time increased as cue reliability decreased and that trials with invalid cues had longer reaction times than trials with valid cues. MEG channel analysis showed that during the late cue period the power of the beta-band from left mid-anterior channels, contralateral to the responding hand, correlated with the reliability of the cue. This effect was source localized over a large motor-related cortical and subcortical network. In addition, during invalid-cue trials there was a phasic increase of theta-band power following target onset from left posterior channels, localized to the left occipito-parietal cortex. Furthermore, the theta-beta cross-frequency coupling between left mid-occipital and motor cortex transiently increased before responses to invalid-cue trials. In conclusion, beta-band power in motor-related areas reflected the reliability of directional information used during motor preparation, whereas phasic theta-band activity may have signaled whether the target was at the expected location or not. These results elucidate mechanisms of interaction between attentional and motor processes.
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Affiliation(s)
- Charidimos Tzagarakis
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, United States.,Veterans Affairs Health Care System, Minneapolis, MN, United States
| | - Sarah West
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, United States
| | - Giuseppe Pellizzer
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, United States.,Veterans Affairs Health Care System, Minneapolis, MN, United States.,Department of Neurology, University of Minnesota, Minneapolis, MN, United States
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103
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Khan H, Sami MB, Litvak V. The utility of Magnetoencephalography in multiple sclerosis - A systematic review. NEUROIMAGE-CLINICAL 2021; 32:102814. [PMID: 34537682 PMCID: PMC8455859 DOI: 10.1016/j.nicl.2021.102814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 08/28/2021] [Accepted: 08/30/2021] [Indexed: 01/29/2023]
Abstract
We conducted a Systematic Review of studies, looking at 30 studies from 13 centres. MS patients had reduced power in some induced responses (motor beta, visual gamma). Increased latency and reduced connectivity were seen for somatosensory evoked fields. There was an association between upper alpha connectivity and cognitive function. MEG shows promise, although work is too preliminary to recommend current clinical use.
Introduction Magnetoencephalography (MEG), allows for a high degree temporal and spatial accuracy in recording cortical oscillatory activity and evoked fields. To date, no review has been undertaken to synthesise all MEG studies in Multiple Sclerosis (MS). We undertook a Systematic Review of the utility of MEG in MS. Methods We identified MEG studies carried out in MS using EMBASE, Medline, Cochrane, TRIP and Psychinfo databases. We included original research articles with a cohort of minimum of five multiple sclerosis patients and quantifying of at least one MEG parameter. We used a modified version of the JBI (mJBI) for case-control studies to assess for risk of bias. Results We identified 30 studies from 13 centres involving at least 433 MS patients and 347 controls. We found evidence that MEG shows perturbed activity (most commonly reduced power modulations), reduced connectivity and association with altered clinical function in Multiple Sclerosis. Specific replicated findings were decreased motor induced responses in the beta band, diminished increase of gamma power after visual stimulation, increased latency and reduced connectivity for somatosensory evoked fields. There was an association between upper alpha connectivity and cognitive measures in people with MS. Overall studies were of moderate quality (mean mJBI score 6.7). Discussion We find evidence for the utility of MEG in Multiple Sclerosis. Event-related designs are of particular value and show replicability between centres. At this stage, it is not clear whether these changes are specific to Multiple Sclerosis or are also observable in other diseases. Further studies should look to explore cognitive control in more depth using in-task designs and undertake longitudinal studies to determine whether these changes have prognostic value.
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Affiliation(s)
- H Khan
- UCL Queen's Square Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom; Queen's Medical Centre Nottingham, Clifton Boulevard, Derby Rd, Nottingham NG7 2UH, United Kingdom.
| | - M B Sami
- Institute of Mental Health, Jubilee Campus, University of Nottingham Innovation Park, Triumph Road, Nottingham NG7 2TU, United Kingdom
| | - V Litvak
- UCL Queen's Square Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
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104
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Jia Z, Lin Y, Wang J, Ning X, He Y, Zhou R, Zhou Y, Lehman LWH. Multi-View Spatial-Temporal Graph Convolutional Networks With Domain Generalization for Sleep Stage Classification. IEEE Trans Neural Syst Rehabil Eng 2021; 29:1977-1986. [PMID: 34487495 PMCID: PMC8556658 DOI: 10.1109/tnsre.2021.3110665] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Sleep stage classification is essential for sleep assessment and disease diagnosis. Although previous attempts to classify sleep stages have achieved high classification performance, several challenges remain open: 1) How to effectively utilize time-varying spatial and temporal features from multi-channel brain signals remains challenging. Prior works have not been able to fully utilize the spatial topological information among brain regions. 2) Due to the many differences found in individual biological signals, how to overcome the differences of subjects and improve the generalization of deep neural networks is important. 3) Most deep learning methods ignore the interpretability of the model to the brain. To address the above challenges, we propose a multi-view spatial-temporal graph convolutional networks (MSTGCN) with domain generalization for sleep stage classification. Specifically, we construct two brain view graphs for MSTGCN based on the functional connectivity and physical distance proximity of the brain regions. The MSTGCN consists of graph convolutions for extracting spatial features and temporal convolutions for capturing the transition rules among sleep stages. In addition, attention mechanism is employed for capturing the most relevant spatial-temporal information for sleep stage classification. Finally, domain generalization and MSTGCN are integrated into a unified framework to extract subject-invariant sleep features. Experiments on two public datasets demonstrate that the proposed model outperforms the state-of-the-art baselines.
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105
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Wang H, Liu X, Li J, Xu T, Bezerianos A, Sun Y, Wan F. Driving Fatigue Recognition With Functional Connectivity Based on Phase Synchronization. IEEE Trans Cogn Dev Syst 2021. [DOI: 10.1109/tcds.2020.2985539] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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106
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Gschwandtner U, Bogaarts G, Chaturvedi M, Hatz F, Meyer A, Fuhr P, Roth V. Dynamic Functional Connectivity of EEG: From Identifying Fingerprints to Gender Differences to a General Blueprint for the Brain's Functional Organization. Front Neurosci 2021; 15:683633. [PMID: 34456669 PMCID: PMC8385669 DOI: 10.3389/fnins.2021.683633] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 06/23/2021] [Indexed: 11/13/2022] Open
Abstract
An individual's brain functional organization is unique and can reliably be observed using modalities such as functional magnetic resonance imaging (fMRI). Here we demonstrate that a quantification of the dynamics of functional connectivity (FC) as measured using electroencephalography (EEG) offers an alternative means of observing an individual's brain functional organization. Using data from both healthy individuals as well as from patients with Parkinson's disease (PD) (n = 103 healthy individuals, n = 57 PD patients), we show that “dynamic FC” (DFC) profiles can be used to identify individuals in a large group. Furthermore, we show that DFC profiles predict gender and exhibit characteristics shared both among individuals as well as between both hemispheres. Furthermore, DFC profile characteristics are frequency band specific, indicating that they reflect distinct processes in the brain. Our empirically derived method of DFC demonstrates the potential of studying the dynamics of the functional organization of the brain using EEG.
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Affiliation(s)
- Ute Gschwandtner
- Department of Neurology and Neurophysiology, University Hospital of Basel, Basel, Switzerland
| | - Guy Bogaarts
- Department of Neurology and Neurophysiology, University Hospital of Basel, Basel, Switzerland.,Department of Mathematics and Computer Science, University of Basel, Basel, Switzerland
| | - Menorca Chaturvedi
- Department of Neurology and Neurophysiology, University Hospital of Basel, Basel, Switzerland
| | - Florian Hatz
- Department of Neurology and Neurophysiology, University Hospital of Basel, Basel, Switzerland
| | - Antonia Meyer
- Department of Neurology and Neurophysiology, University Hospital of Basel, Basel, Switzerland
| | - Peter Fuhr
- Department of Neurology and Neurophysiology, University Hospital of Basel, Basel, Switzerland
| | - Volker Roth
- Department of Mathematics and Computer Science, University of Basel, Basel, Switzerland
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107
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Yao B, Taylor JR, Banks B, Kotz SA. Reading direct speech quotes increases theta phase-locking: Evidence for cortical tracking of inner speech? Neuroimage 2021; 239:118313. [PMID: 34175425 DOI: 10.1016/j.neuroimage.2021.118313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/28/2021] [Accepted: 06/24/2021] [Indexed: 11/25/2022] Open
Abstract
Growing evidence shows that theta-band (4-7 Hz) activity in the auditory cortex phase-locks to rhythms of overt speech. Does theta activity also encode the rhythmic dynamics of inner speech? Previous research established that silent reading of direct speech quotes (e.g., Mary said: "This dress is lovely!") elicits more vivid inner speech than indirect speech quotes (e.g., Mary said that the dress was lovely). As we cannot directly track the phase alignment between theta activity and inner speech over time, we used EEG to measure the brain's phase-locked responses to the onset of speech quote reading. We found that direct (vs. indirect) quote reading was associated with increased theta phase synchrony over trials at 250-500 ms post-reading onset, with sources of the evoked activity estimated in the speech processing network. An eye-tracking control experiment confirmed that increased theta phase synchrony in direct quote reading was not driven by eye movement patterns, and more likely reflects synchronous phase resetting at the onset of inner speech. These findings suggest a functional role of theta phase modulation in reading-induced inner speech.
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Affiliation(s)
- Bo Yao
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, United Kingdom.
| | - Jason R Taylor
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Briony Banks
- Department of Psychology, Lancaster University, Lancaster LA1 4YF, United Kingdom
| | - Sonja A Kotz
- Department of Neuropsychology & Psychopharmacology, Maastricht University, Maastricht 6211 LK, Netherlands; Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig 04103, Germany
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108
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Tani R, Kashimori Y. Coordination of top-down influence on V1 responses by interneurons and brain rhythms. Biosystems 2021; 207:104452. [PMID: 34139291 DOI: 10.1016/j.biosystems.2021.104452] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 02/25/2021] [Accepted: 06/05/2021] [Indexed: 11/18/2022]
Abstract
Top-down processing in neocortex underlies functions such as prediction, expectation, and attention. Visual systems have much feedback connection that carries information of behavioral context. Top-down signals along feedback pathways modulate the representation of visual information in early visual areas such as primary visual cortex (V1). Recent studies have shown further that beta rhythms are responsible for the transmission of behavioral-context information to lower visual areas. However, the mechanism underlying top-down influence and the role of brain rhythms in top-down processing are poorly understood. To address these issues, we focus on experimental studies on top-down influence in visual perceptual tasks. We develop a model of visual system, in which early visual areas are subjected to top-down influence from a recognition area. We show that task-relevant information in early visual areas is regulated by a push-pull effect, produced by somatostatin-expressing interneurons and top-down signal. We also show that task-context information is coordinated by the phase-phase coupling of beta rhythms, while the local, task-relevant stimulus features are enhanced by the phase-amplitude coupling of beta and gamma rhythms. Furthermore, the feedback from a higher visual area such as secondary visual area facilitates the gating of task-relevant information in V1. The results provide insights to understanding the roles of inhibitory interneurons and brain rhythms in top-down influence on information processing in early visual areas.
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Affiliation(s)
- Ryo Tani
- Department of Engineering Science, University of Electro-Communications, Chofu, Tokyo, 182-8585, Japan.
| | - Yoshiki Kashimori
- Department of Engineering Science, University of Electro-Communications, Chofu, Tokyo, 182-8585, Japan
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109
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Alotaibi N, Maharatna K. Classification of Autism Spectrum Disorder From EEG-Based Functional Brain Connectivity Analysis. Neural Comput 2021; 33:1914-1941. [PMID: 34411269 DOI: 10.1162/neco_a_01394] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 02/04/2021] [Indexed: 11/04/2022]
Abstract
Autism is a psychiatric condition that is typically diagnosed with behavioral assessment methods. Recent years have seen a rise in the number of children with autism. Since this could have serious health and socioeconomic consequences, it is imperative to investigate how to develop strategies for an early diagnosis that might pave the way to an adequate intervention. In this study, the phase-based functional brain connectivity derived from electroencephalogram (EEG) in a machine learning framework was used to classify the children with autism and typical children in an experimentally obtained data set of 12 autism spectrum disorder (ASD) and 12 typical children. Specifically, the functional brain connectivity networks have quantitatively been characterized by graph-theoretic parameters computed from three proposed approaches based on a standard phase-locking value, which were used as the features in a machine learning environment. Our study was successfully classified between two groups with approximately 95.8% accuracy, 100% sensitivity, and 92% specificity through the trial-averaged phase-locking value (PLV) approach and cubic support vector machine (SVM). This work has also shown that significant changes in functional brain connectivity in ASD children have been revealed at theta band using the aggregated graph-theoretic features. Therefore, the findings from this study offer insight into the potential use of functional brain connectivity as a tool for classifying ASD children.
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Affiliation(s)
- Noura Alotaibi
- Department of Electronics and Computer Science, University of Southampton, Southampton, SO17 1BJ, UK
| | - Koushik Maharatna
- Department of Electronics and Computer Science, University of Southampton, Southampton, SO17 1BJ, UK
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110
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Safavi S, Logothetis NK, Besserve M. From Univariate to Multivariate Coupling Between Continuous Signals and Point Processes: A Mathematical Framework. Neural Comput 2021; 33:1751-1817. [PMID: 34411270 DOI: 10.1162/neco_a_01389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 01/19/2021] [Indexed: 11/04/2022]
Abstract
Time series data sets often contain heterogeneous signals, composed of both continuously changing quantities and discretely occurring events. The coupling between these measurements may provide insights into key underlying mechanisms of the systems under study. To better extract this information, we investigate the asymptotic statistical properties of coupling measures between continuous signals and point processes. We first introduce martingale stochastic integration theory as a mathematical model for a family of statistical quantities that include the phase locking value, a classical coupling measure to characterize complex dynamics. Based on the martingale central limit theorem, we can then derive the asymptotic gaussian distribution of estimates of such coupling measure that can be exploited for statistical testing. Second, based on multivariate extensions of this result and random matrix theory, we establish a principled way to analyze the low-rank coupling between a large number of point processes and continuous signals. For a null hypothesis of no coupling, we establish sufficient conditions for the empirical distribution of squared singular values of the matrix to converge, as the number of measured signals increases, to the well-known Marchenko-Pastur (MP) law, and the largest squared singular value converges to the upper end of the MP support. This justifies a simple thresholding approach to assess the significance of multivariate coupling. Finally, we illustrate with simulations the relevance of our univariate and multivariate results in the context of neural time series, addressing how to reliably quantify the interplay between multichannel local field potential signals and the spiking activity of a large population of neurons.
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Affiliation(s)
- Shervin Safavi
- MPI for Biological Cybernetics, and IMPRS for Cognitive and Systems Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Nikos K Logothetis
- MPI for Biological Cybernetics, 72076 Tübingen, Germany; International Center for Primate Brain Research, Songjiang, Shanghai 200031, China; and University of Manchester, Manchester M13 9PL, U.K.
| | - Michel Besserve
- MPI for Biological Cybernetics and MPI for Intelligent Systems, 72076 Tübingen, Germany
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111
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Shan X, Huo S, Yang L, Cao J, Zou J, Chen L, Sarrigiannis PG, Zhao Y. A Revised Hilbert-Huang Transformation to Track Non-Stationary Association of Electroencephalography Signals. IEEE Trans Neural Syst Rehabil Eng 2021; 29:841-851. [PMID: 33909567 DOI: 10.1109/tnsre.2021.3076311] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The time-varying cross-spectrum method has been used to effectively study transient and dynamic brain functional connectivity between non-stationary electroencephalography (EEG) signals. Wavelet-based cross-spectrum is one of the most widely implemented methods, but it is limited by the spectral leakage caused by the finite length of the basic function that impacts the time and frequency resolutions. This paper proposes a new time-frequency brain functional connectivity analysis framework to track the non-stationary association of two EEG signals based on a Revised Hilbert-Huang Transform (RHHT). The framework can estimate the cross-spectrum of decomposed components of EEG, followed by a surrogate significance test. The results of two simulation examples demonstrate that, within a certain statistical confidence level, the proposed framework outperforms the wavelet-based method in terms of accuracy and time-frequency resolution. A case study on classifying epileptic patients and healthy controls using interictal seizure-free EEG data is also presented. The result suggests that the proposed method has the potential to better differentiate these two groups benefiting from the enhanced measure of dynamic time-frequency association.
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112
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Hatlestad-Hall C, Bruña R, Syvertsen MR, Erichsen A, Andersson V, Vecchio F, Miraglia F, Rossini PM, Renvall H, Taubøll E, Maestú F, Haraldsen IH. Source-level EEG and graph theory reveal widespread functional network alterations in focal epilepsy. Clin Neurophysiol 2021; 132:1663-1676. [PMID: 34044189 DOI: 10.1016/j.clinph.2021.04.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 03/19/2021] [Accepted: 04/20/2021] [Indexed: 01/15/2023]
Abstract
OBJECTIVE The hypersynchronous neuronal activity associated with epilepsy causes widespread functional network disruptions extending beyond the epileptogenic zone. This altered network topology is considered a mediator for non-seizure symptoms, such as cognitive impairment. The aim of this study was to investigate functional network alterations in focal epilepsy patients with good seizure control and high quality of life. METHODS We compared twenty-two focal epilepsy patients and sixteen healthy controls on graph metrics derived from functional connectivity of source-level resting-state EEG. Graph metrics were calculated over a range of network densities in five frequency bands. RESULTS We observed a significantly increased small world index in patients relative to controls. On the local level, two left-hemisphere regions displayed a shift towards greater alpha band "hubness". The findings were not mediated by age, sex or education, nor by age of epilepsy onset, duration or focus lateralisation. CONCLUSIONS Widespread functional network alterations are evident in focal epilepsy, even in a cohort characterised by successful anti-seizure medication therapy and high quality of life. These findings might support the position that functional network analysis could hold clinical relevance for epilepsy. SIGNIFICANCE Focal epilepsy is accompanied by global and local functional network aberrancies which might be implied in the sustenance of non-seizure symptoms.
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Affiliation(s)
| | - Ricardo Bruña
- Center for Biomedical Technology, Technical University of Madrid, Pozuelo de Alarcón, Spain; Department of Experimental Psychology, Complutense University of Madrid, Pozuelo de Alarcón, Spain; Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain.
| | - Marte Roa Syvertsen
- Department of Neurology, Drammen Hospital, Vestre Viken Health Care Trust, Drammen, Norway.
| | - Aksel Erichsen
- Department of Neurology, Oslo University Hospital, Oslo, Norway; Department of Nuclear Medicine, Oslo University Hospital, Oslo, Norway.
| | | | - Fabrizio Vecchio
- Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Pisana, Rome, Italy.
| | - Francesca Miraglia
- Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Pisana, Rome, Italy.
| | - Paolo M Rossini
- Brain Connectivity Laboratory, Department of Neuroscience and Neurorehabilitation, IRCCS San Raffaele Pisana, Rome, Italy.
| | - Hanna Renvall
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland; BioMag Laboratory, HUS Diagnostic Center, Helsinki University Hospital, University of Helsinki and Aalto University School of Science, Helsinki, Finland.
| | - Erik Taubøll
- Department of Neurology, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
| | - Fernando Maestú
- Center for Biomedical Technology, Technical University of Madrid, Pozuelo de Alarcón, Spain; Department of Experimental Psychology, Complutense University of Madrid, Pozuelo de Alarcón, Spain; Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain.
| | - Ira H Haraldsen
- Department of Neurology, Oslo University Hospital, Oslo, Norway.
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113
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Differential contributions of synaptic and intrinsic inhibitory currents to speech segmentation via flexible phase-locking in neural oscillators. PLoS Comput Biol 2021; 17:e1008783. [PMID: 33852573 PMCID: PMC8104450 DOI: 10.1371/journal.pcbi.1008783] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/07/2021] [Accepted: 02/05/2021] [Indexed: 01/07/2023] Open
Abstract
Current hypotheses suggest that speech segmentation—the initial division and grouping of the speech stream into candidate phrases, syllables, and phonemes for further linguistic processing—is executed by a hierarchy of oscillators in auditory cortex. Theta (∼3-12 Hz) rhythms play a key role by phase-locking to recurring acoustic features marking syllable boundaries. Reliable synchronization to quasi-rhythmic inputs, whose variable frequency can dip below cortical theta frequencies (down to ∼1 Hz), requires “flexible” theta oscillators whose underlying neuronal mechanisms remain unknown. Using biophysical computational models, we found that the flexibility of phase-locking in neural oscillators depended on the types of hyperpolarizing currents that paced them. Simulated cortical theta oscillators flexibly phase-locked to slow inputs when these inputs caused both (i) spiking and (ii) the subsequent buildup of outward current sufficient to delay further spiking until the next input. The greatest flexibility in phase-locking arose from a synergistic interaction between intrinsic currents that was not replicated by synaptic currents at similar timescales. Flexibility in phase-locking enabled improved entrainment to speech input, optimal at mid-vocalic channels, which in turn supported syllabic-timescale segmentation through identification of vocalic nuclei. Our results suggest that synaptic and intrinsic inhibition contribute to frequency-restricted and -flexible phase-locking in neural oscillators, respectively. Their differential deployment may enable neural oscillators to play diverse roles, from reliable internal clocking to adaptive segmentation of quasi-regular sensory inputs like speech. Oscillatory activity in auditory cortex is believed to play an important role in auditory and speech processing. One suggested function of these rhythms is to divide the speech stream into candidate phonemes, syllables, words, and phrases, to be matched with learned linguistic templates. This requires brain rhythms to flexibly synchronize with regular acoustic features of the speech stream. How neuronal circuits implement this task remains unknown. In this study, we explored the contribution of inhibitory currents to flexible phase-locking in neuronal theta oscillators, believed to perform initial syllabic segmentation. We found that a combination of specific intrinsic inhibitory currents at multiple timescales, present in a large class of cortical neurons, enabled exceptionally flexible phase-locking, which could be used to precisely segment speech by identifying vowels at mid-syllable. This suggests that the cells exhibiting these currents are a key component in the brain’s auditory and speech processing architecture.
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114
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Carrasco-Gómez M, Keijzer HM, Ruijter BJ, Bruña R, Tjepkema-Cloostermans MC, Hofmeijer J, van Putten MJAM. EEG functional connectivity contributes to outcome prediction of postanoxic coma. Clin Neurophysiol 2021; 132:1312-1320. [PMID: 33867260 DOI: 10.1016/j.clinph.2021.02.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 01/19/2021] [Accepted: 02/09/2021] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To investigate the additional value of EEG functional connectivity features, in addition to non-coupling EEG features, for outcome prediction of comatose patients after cardiac arrest. METHODS Prospective, multicenter cohort study. Coherence, phase locking value, and mutual information were calculated in 19-channel EEGs at 12 h, 24 h and 48 h after cardiac arrest. Three sets of machine learning classification models were trained and validated with functional connectivity, EEG non-coupling features, and a combination of these. Neurological outcome was assessed at six months and categorized as "good" (Cerebral Performance Category [CPC] 1-2) or "poor" (CPC 3-5). RESULTS We included 594 patients (46% good outcome). A sensitivity of 51% (95% CI: 34-56%) at 100% specificity in predicting poor outcome was achieved by the best functional connectivity-based classifier at 12 h after cardiac arrest, while the best non-coupling-based model reached a sensitivity of 32% (0-54%) at 100% specificity using data at 12 h and 48 h. Combination of both sets of features achieved a sensitivity of 73% (50-77%) at 100% specificity. CONCLUSION Functional connectivity measures improve EEG based prediction models for poor outcome of postanoxic coma. SIGNIFICANCE Functional connectivity features derived from early EEG hold potential to improve outcome prediction of coma after cardiac arrest.
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Affiliation(s)
- Martín Carrasco-Gómez
- Laboratory of Cognitive and Computational Neuroscience (LNCyC), Centre for Biomedical Technology, Universidad Politécnica de Madrid, Spain; Biomedical Research Networking Center in Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain.
| | - Hanneke M Keijzer
- Department of Neurology, Rijnstate Hospital, Arnhem, the Netherlands; Department of Neurology, Donders Institute for Brain, Cognition, and Behaviour, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Barry J Ruijter
- Clinical Neurophysiology (CNPH), TechMed Centre, University of Twente, the Netherlands
| | - Ricardo Bruña
- Laboratory of Cognitive and Computational Neuroscience (LNCyC), Centre for Biomedical Technology, Universidad Politécnica de Madrid, Spain; Biomedical Research Networking Center in Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
| | - Marleen C Tjepkema-Cloostermans
- Clinical Neurophysiology (CNPH), TechMed Centre, University of Twente, the Netherlands; Neurocentrum, Medisch SpectrumTwente, Enschede, the Netherlands
| | - Jeannette Hofmeijer
- Clinical Neurophysiology (CNPH), TechMed Centre, University of Twente, the Netherlands; Department of Neurology, Rijnstate Hospital, Arnhem, the Netherlands
| | - Michel J A M van Putten
- Clinical Neurophysiology (CNPH), TechMed Centre, University of Twente, the Netherlands; Neurocentrum, Medisch SpectrumTwente, Enschede, the Netherlands
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Hansen J, Omland P, Nilsen K, Sand T, Matre D. Experimental sleep restriction increases latency jitter in pain elicited cortical responses. Heliyon 2021; 7:e06188. [PMID: 33659735 PMCID: PMC7890207 DOI: 10.1016/j.heliyon.2021.e06188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 10/31/2020] [Accepted: 01/31/2021] [Indexed: 12/16/2022] Open
Abstract
Objective Previous studies have shown increased pain scores to painful stimulation after experimental sleep restriction, but reduced or unchanged magnitude of the event related potentials (ERPs) when averaged in the time-domain. However, some studies found increased response magnitude when averaging in the time-frequency domain. The aim of this study was to determine whether ERP-latency jitter may contribute to this discrepancy. Methods Ninety painful electrical stimuli were given to 21 volunteers after two nights of 50% sleep restriction and after two nights of habitual sleep. ERPs were analyzed in the time-domain (N2-and P2-peaks) and time-frequency domain (power spectral density). We quantified latency jitter by the mean consecutive difference (MCD) between single-trial peak latencies and by phase locking value (PLV) across trials. Results P2-MCD increased from 20.4 ± 2.1 ms after habitual sleep to 24.3 ± 2.2 ms after sleep restriction (19%, p = 0.038) and PLV decreased from 0.582 ± 0.015 after habitual sleep to 0.536 ± 0.015 after sleep restriction (7.9%, p = 0.009). We found no difference for N2-MCD. Conclusions Our results indicate that partial sleep restriction increase latency jitter in cortical responses to experimental pain. Significance Latency jitter may contribute to the discrepancies between ERP-responses in the time-frequency domain and time-domain. Latency jitter should be considered when ERPs are analyzed.
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Affiliation(s)
- J.O. Hansen
- NTNU, Norwegian University of Science and Technology, Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Postboks 8905, 7491, Trondheim, Norway
- Corresponding author.
| | - P.M. Omland
- NTNU, Norwegian University of Science and Technology, Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Postboks 8905, 7491, Trondheim, Norway
- St. Olavs Hospital, Department of Neurology and Clinical Neurophysiology, Postboks 3250 Sluppen, 7006, Trondheim, Norway
| | - K.B. Nilsen
- NTNU, Norwegian University of Science and Technology, Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Postboks 8905, 7491, Trondheim, Norway
- National Institute of Occupational Health, Department of Work Psychology and Physiology, Gydas vei 8, 0363, Oslo, Norway
| | - T. Sand
- NTNU, Norwegian University of Science and Technology, Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Postboks 8905, 7491, Trondheim, Norway
- St. Olavs Hospital, Department of Neurology and Clinical Neurophysiology, Postboks 3250 Sluppen, 7006, Trondheim, Norway
| | - D. Matre
- National Institute of Occupational Health, Department of Work Psychology and Physiology, Gydas vei 8, 0363, Oslo, Norway
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Ayrolles A, Brun F, Chen P, Djalovski A, Beauxis Y, Delorme R, Bourgeron T, Dikker S, Dumas G. HyPyP: a Hyperscanning Python Pipeline for inter-brain connectivity analysis. Soc Cogn Affect Neurosci 2021; 16:72-83. [PMID: 33031496 PMCID: PMC7812632 DOI: 10.1093/scan/nsaa141] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 09/22/2020] [Accepted: 10/07/2020] [Indexed: 12/24/2022] Open
Abstract
The bulk of social neuroscience takes a 'stimulus-brain' approach, typically comparing brain responses to different types of social stimuli, but most of the time in the absence of direct social interaction. Over the last two decades, a growing number of researchers have adopted a 'brain-to-brain' approach, exploring similarities between brain patterns across participants as a novel way to gain insight into the social brain. This methodological shift has facilitated the introduction of naturalistic social stimuli into the study design (e.g. movies) and, crucially, has spurred the development of new tools to directly study social interaction, both in controlled experimental settings and in more ecologically valid environments. Specifically, 'hyperscanning' setups, which allow the simultaneous recording of brain activity from two or more individuals during social tasks, has gained popularity in recent years. However, currently, there is no agreed-upon approach to carry out such 'inter-brain connectivity analysis', resulting in a scattered landscape of analysis techniques. To accommodate a growing demand to standardize analysis approaches in this fast-growing research field, we have developed Hyperscanning Python Pipeline, a comprehensive and easy open-source software package that allows (social) neuroscientists to carry-out and to interpret inter-brain connectivity analyses.
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Affiliation(s)
- Anaël Ayrolles
- Department of Neuroscience, Institut Pasteur, Paris, France
- Child and Adolescent Psychiatry Department, Assistance Publique - Hôpitaux de Paris, Robert Debré Hospital, Paris, France
| | - Florence Brun
- Department of Neuroscience, Institut Pasteur, Paris, France
| | - Phoebe Chen
- Department of Psychology, New York University, New York City, USA
| | - Amir Djalovski
- Baruch Ivcher School of Psychology, Center for Developmental Social Neuroscience, Interdiscilinary Center Herzliya, Baruch Ivcher School of Psychology, Herzliya, Israel
- Department of Psychology, Bar-Ilan University, Ramat Gan, Israel
| | - Yann Beauxis
- Department of Neuroscience, Institut Pasteur, Paris, France
| | - Richard Delorme
- Department of Neuroscience, Institut Pasteur, Paris, France
- Child and Adolescent Psychiatry Department, Assistance Publique - Hôpitaux de Paris, Robert Debré Hospital, Paris, France
| | | | - Suzanne Dikker
- Department of Psychology, New York University, New York City, USA
- Department of Clinical Psychology, Free University Amsterdam, Amsterdam, The Netherlands
| | - Guillaume Dumas
- Department of Neuroscience, Institut Pasteur, Paris, France
- Center for Complex Systems and Brain Sciences, Florida Atlantic University, Center for Complex Systems and Brain Sciences, Boca Raton, FL, USA
- Departement of Psychiatry, Université de Montréal, Montreal, QC, Canada
- Precision Psychiatry and Social Physiology laboratory, CHU Sainte-Justine Centre de Recherche, Precision Psychiatry and Social Physiology Laboratory, Montreal, QC, Canada
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Dheer P, Pati S, Chowdhury KK, Majumdar KK. Enhanced gamma band mutual information is associated with impaired consciousness during temporal lobe seizures. Heliyon 2021; 6:e05769. [PMID: 33409386 PMCID: PMC7773881 DOI: 10.1016/j.heliyon.2020.e05769] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 07/24/2020] [Accepted: 12/14/2020] [Indexed: 11/24/2022] Open
Abstract
Background Epileptic seizures are characterized by aberrant synchronization. We hypothesized that higher synchronization across the seizure onset zone (SOZ) channels during a temporal lobe seizure contributes to impaired consciousness. New method All symmetric bivariate synchronization measures were extended to multivariate measure by a principal component analysis (PCA) based technique. A novel nonparametric method has been proposed to test the statistical significance between increased synchronization across the seizure onset zone (SOZ) channels and reduced consciousness. Results Increased synchronization in the gamma band towards seizure termination significantly contributes to impaired consciousness (p < 0.1). Synchronization reaches its peak in the extratemporal region (frontal lobe) ahead of the temporal region (p < 0.05). Synchronization is prominent in beta and gamma bands by most methods and it is more in the second half of seizure duration than in the first (p < 0.05). Conclusions Mutual information is the only synchronization measure out of the six that we studied, whose increase can be associated with the loss of consciousness in a statistically significant way.
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Affiliation(s)
- Puneet Dheer
- Systems Science and Informatics Unit, Indian Statistical Institute, 8th Mile, Mysore Road, Bangalore, India, 560059
| | - Sandipan Pati
- UAB Epilepsy Center, Department of Neurology, University of Alabama at Birmingham, CIRC 312, 1719 6th Avenue South, Birmingham, AL, 35294, USA
| | - Kalyan Kumar Chowdhury
- Statistical Quality Control Unit, Indian Statistical Institute, 8th Mile, Mysore Road, Bangalore, 560059, India
| | - Kaushik Kumar Majumdar
- Systems Science and Informatics Unit, Indian Statistical Institute, 8th Mile, Mysore Road, Bangalore, India, 560059
- Corresponding author.
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Phase-locking of resting-state brain networks with the gastric basal electrical rhythm. PLoS One 2021; 16:e0244756. [PMID: 33400717 PMCID: PMC7785240 DOI: 10.1371/journal.pone.0244756] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 12/15/2020] [Indexed: 11/19/2022] Open
Abstract
A network of myenteric interstitial cells of Cajal in the corpus of the stomach serves as its "pacemaker", continuously generating a ca 0.05 Hz electrical slow wave, which is transmitted to the brain chiefly by vagal afferents. A recent study combining resting-state functional MRI (rsfMRI) with concurrent surface electrogastrography (EGG), with cutaneous electrodes placed on the epigastrium, found 12 brain regions with activity that was significantly phase-locked with this gastric basal electrical rhythm. Therefore, we asked whether fluctuations in brain resting state networks (RSNs), estimated using a spatial independent component analysis (ICA) approach, might be synchronized with the stomach. In the present study, in order to determine whether any RSNs are phase-locked with the gastric rhythm, an individual participant underwent 22 scanning sessions; in each, two 15-minute runs of concurrent EGG and rsfMRI data were acquired. EGG data from three sessions had weak gastric signals and were excluded; the other 19 sessions yielded a total of 9.5 hours of data. The rsfMRI data were analyzed using group ICA; RSN time courses were estimated; for each run, the phase-locking value (PLV) was computed between each RSN and the gastric signal. To assess statistical significance, PLVs from all pairs of "mismatched" data (EGG and rsfMRI data acquired on different days) were used as surrogate data to generate a null distribution for each RSN. Of a total of 18 RSNs, three were found to be significantly phase-locked with the basal gastric rhythm, namely, a cerebellar network, a dorsal somatosensory-motor network, and a default mode network. Disruptions to the gut-brain axis, which sustains interoceptive feedback between the central nervous system and the viscera, are thought to be involved in various disorders; manifestation of the infra-slow rhythm of the stomach in brain rsfMRI data could be useful for studies in clinical populations.
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Bruña R, Pereda E. Multivariate extension of phase synchronization improves the estimation of region-to-region source space functional connectivity. BRAIN MULTIPHYSICS 2021. [DOI: 10.1016/j.brain.2021.100021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Sánchez-Dinorín G, Rodríguez-Violante M, Cervantes-Arriaga A, Navarro-Roa C, Ricardo-Garcell J, Rodríguez-Camacho M, Solís-Vivanco R. Frontal functional connectivity and disease duration interactively predict cognitive decline in Parkinson's disease. Clin Neurophysiol 2020; 132:510-519. [PMID: 33450572 DOI: 10.1016/j.clinph.2020.11.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/25/2020] [Accepted: 11/16/2020] [Indexed: 01/27/2023]
Abstract
OBJECTIVE Cognitive decline does not always follow a predictable course in Parkinson's disease (PD), with some patients remaining stable while others meet criteria for dementia from early stages. Functional connectivity has been proposed as a good correlate of cognitive decline in PD, although it has not been explored whether the association between this connectivity and cognitive ability is influenced by disease duration, which was our objective. METHODS We included 30 patients with PD and 15 healthy controls (HC). Six cognitive domains were estimated based on neuropsychological assessment. Phase-based connectivity at frontal and posterior cortical regions was estimated from a resting EEG. RESULTS The PD group showed significant impairment for the executive, visuospatial, and language domains compared with HC. Increased connectivity at frontal regions was also found in the PD group. Frontal delta and theta connectivity negatively influenced general cognition and visuospatial performance, but this association was moderated by disease duration, with increased connectivity predicting worse performance after 8 years of disease duration. CONCLUSION Subtle neurophysiological changes underlie cognitive decline along PD progression, especially around a decade after motor symptoms onset. SIGNIFICANCE Connectivity of EEG slow waves at frontal regions might be used as a predictor of cognitive decline in PD.
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Affiliation(s)
- Gerardo Sánchez-Dinorín
- Neuropsychology Laboratory, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez (INNN), Mexico City, Mexico; Faculty of Psychology, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | | | | | | | | | | | - Rodolfo Solís-Vivanco
- Neuropsychology Laboratory, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez (INNN), Mexico City, Mexico; Faculty of Psychology, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico.
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Frusque G, Borgnat P, Gonçalves P, Jung J. Semi-automatic Extraction of Functional Dynamic Networks Describing Patient's Epileptic Seizures. Front Neurol 2020; 11:579725. [PMID: 33362688 PMCID: PMC7759641 DOI: 10.3389/fneur.2020.579725] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/08/2020] [Indexed: 11/24/2022] Open
Abstract
Intracranial electroencephalography (EEG) studies using stereotactic EEG (SEEG) have shown that during seizures, epileptic activity spreads across several anatomical regions from the seizure onset zone toward remote brain areas. A full and objective characterization of this patient-specific time-varying network is crucial for optimal surgical treatment. Functional connectivity (FC) analysis of SEEG signals recorded during seizures enables to describe the statistical relations between all pairs of recorded signals. However, extracting meaningful information from those large datasets is time consuming and requires high expertise. In the present study, we first propose a novel method named Brain-wide Time-varying Network Decomposition (BTND) to characterize the dynamic epileptogenic networks activated during seizures in individual patients recorded with SEEG electrodes. The method provides a number of pathological FC subgraphs with their temporal course of activation. The method can be applied to several seizures of the patient to extract reproducible subgraphs. Second, we compare the activated subgraphs obtained by the BTND method with visual interpretation of SEEG signals recorded in 27 seizures from nine different patients. As a whole, we found that activated subgraphs corresponded to brain regions involved during the course of the seizures and their time course was highly consistent with classical visual interpretation. We believe that the proposed method can complement the visual analysis of SEEG signals recorded during seizures by highlighting and characterizing the most significant parts of epileptic networks with their activation dynamics.
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Affiliation(s)
- Gaëtan Frusque
- Univ Lyon, Inria, CNRS, ENS de Lyon, UCB Lyon 1, LIP UMR 5668, Lyon, France
| | - Pierre Borgnat
- Univ Lyon, CNRS, ENS de Lyon, UCB Lyon 1, Laboratoire de Physique, UMR 5672, Lyon, France
| | - Paulo Gonçalves
- Univ Lyon, Inria, CNRS, ENS de Lyon, UCB Lyon 1, LIP UMR 5668, Lyon, France
| | - Julien Jung
- National Institute of Health and Medical Research U1028/National Center for Scientific Research, Mixed Unit of Research 5292, Lyon Neuroscience Research Center, Lyon, France.,Department of Functional Neurology and Epileptology, Member of the ERN EpiCARE Lyon University Hospital and Lyon 1 University, Lyon, France
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Dellavale D, Velarde OM, Mato G, Urdapilleta E. Complex interplay between spectral harmonicity and different types of cross-frequency couplings in nonlinear oscillators and biologically plausible neural network models. Phys Rev E 2020; 102:062401. [PMID: 33466042 DOI: 10.1103/physreve.102.062401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 11/03/2020] [Indexed: 11/07/2022]
Abstract
Cross-frequency coupling (CFC) refers to the nonlinear interaction between oscillations in different frequency bands, and it is a rather ubiquitous phenomenon that has been observed in a variety of physical and biophysical systems. In particular, the coupling between the phase of slow oscillations and the amplitude of fast oscillations, referred as phase-amplitude coupling (PAC), has been intensively explored in the brain activity recorded from animals and humans. However, the interpretation of these CFC patterns remains challenging since harmonic spectral correlations characterizing nonsinusoidal oscillatory dynamics can act as a confounding factor. Specialized signal processing techniques are proposed to address the complex interplay between spectral harmonicity and different types of CFC, not restricted only to PAC. For this, we provide an in-depth characterization of the time locked index (TLI) as a tool aimed to efficiently quantify the harmonic content of noisy time series. It is shown that the proposed TLI measure is more robust and outperforms traditional phase coherence metrics (e.g., phase locking value, pairwise phase consistency) in several aspects. We found that a nonlinear oscillator under the effect of additive noise can produce spurious CFC with low spectral harmonic content. On the other hand, two coupled oscillatory dynamics with independent fundamental frequencies can produce true CFC with high spectral harmonic content via a rectification mechanism or other post-interaction nonlinear processing mechanisms. These results reveal a complex interplay between CFC and harmonicity emerging in the dynamics of biologically plausible neural network models and more generic nonlinear and parametric oscillators. We show that, contrary to what is usually assumed in the literature, the high harmonic content observed in nonsinusoidal oscillatory dynamics is neither a sufficient nor necessary condition to interpret the associated CFC patterns as epiphenomenal. There is mounting evidence suggesting that the combination of multimodal recordings, specialized signal processing techniques, and theoretical modeling is becoming a required step to completely understand CFC patterns observed in oscillatory rich dynamics of physical and biophysical systems.
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Affiliation(s)
- Damián Dellavale
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica (CNEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCUYO), Av. E. Bustillo 9500, R8402AGP San Carlos de Bariloche, Río Negro, Argentina
| | - Osvaldo Matías Velarde
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica (CNEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCUYO), Av. E. Bustillo 9500, R8402AGP San Carlos de Bariloche, Río Negro, Argentina
| | - Germán Mato
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica (CNEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCUYO), Av. E. Bustillo 9500, R8402AGP San Carlos de Bariloche, Río Negro, Argentina
| | - Eugenio Urdapilleta
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica (CNEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCUYO), Av. E. Bustillo 9500, R8402AGP San Carlos de Bariloche, Río Negro, Argentina
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Ricci L, Assenza G, Pulitano P, Simonelli V, Vollero L, Lanzone J, Mecarelli O, Di Lazzaro V, Tombini M. Measuring the effects of first antiepileptic medication in Temporal Lobe Epilepsy: Predictive value of quantitative-EEG analysis. Clin Neurophysiol 2020; 132:25-35. [PMID: 33248432 DOI: 10.1016/j.clinph.2020.10.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 08/24/2020] [Accepted: 10/05/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To determine the quantitative EEG responses in a population of drug-naïve patients with Temporal Lobe Epilepsy (TLE) after Levetiracetam (LEV) initiation as first antiepileptic drug (AED). We hypothesized that the outcome of AED treatment can be predicted from EEG data in patients with TLE. METHODS Twenty-three patients with TLE and twenty-five healthy controls were examined. Clinical outcome was dichotomized into seizure-free (SF) and non-seizure-free (NSF) after two years of LEV. EEG parameters were compared between healthy controls and patients with TLE at baseline (EEGpre) and after three months of AED therapy (EEGpre-post) and between SF and NSF patients. Receiver Operating Characteristic curves models were built to test whether EEG parameters predicted outcome. RESULTS AED therapy induces an increase in EEG power for Alpha (p = 0.06) and a decrease in Theta (p < 0.05). Connectivity values were lower in SF compared to NSF patients (p < 0.001). Quantitative EEG predicted outcome after LEV treatment with an estimated accuracy varying from 65.2% to 91.3% (area under the curve [AUC] = 0.56-0.93) for EEGpre and from 69.9% to 86.9% (AUC = 0.69-0.94) for EEGpre-post. CONCLUSIONS AED therapy induces EEG modifications in TLE patients, and such modifications are predictive of clinical outcome. SIGNIFICANCE Quantitative EEG may help understanding the effect of AEDs in the central nervous system and offer new prognostic biomarkers for patients with epilepsy.
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Affiliation(s)
- Lorenzo Ricci
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, University Campus Bio-Medico of Rome, via Álvaro del Portillo, 21, 00128 Rome, Italy.
| | - Giovanni Assenza
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, University Campus Bio-Medico of Rome, via Álvaro del Portillo, 21, 00128 Rome, Italy
| | - Patrizia Pulitano
- Department of Neurology and Psychiatry, "Sapienza" University of Rome, Italy
| | - Valerio Simonelli
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, University Campus Bio-Medico of Rome, via Álvaro del Portillo, 21, 00128 Rome, Italy
| | - Luca Vollero
- Unit of Computational Systems and Bioinformatics, Department of Engineering, Campus Bio-Medico University of Rome, Rome, Italy
| | - Jacopo Lanzone
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, University Campus Bio-Medico of Rome, via Álvaro del Portillo, 21, 00128 Rome, Italy
| | - Oriano Mecarelli
- Department of Neurology and Psychiatry, "Sapienza" University of Rome, Italy
| | - Vincenzo Di Lazzaro
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, University Campus Bio-Medico of Rome, via Álvaro del Portillo, 21, 00128 Rome, Italy
| | - Mario Tombini
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, University Campus Bio-Medico of Rome, via Álvaro del Portillo, 21, 00128 Rome, Italy
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Nolte G, Galindo-Leon E, Li Z, Liu X, Engel AK. Mathematical Relations Between Measures of Brain Connectivity Estimated From Electrophysiological Recordings for Gaussian Distributed Data. Front Neurosci 2020; 14:577574. [PMID: 33240037 PMCID: PMC7683718 DOI: 10.3389/fnins.2020.577574] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 10/06/2020] [Indexed: 11/13/2022] Open
Abstract
A large variety of methods exist to estimate brain coupling in the frequency domain from electrophysiological data measured, e.g., by EEG and MEG. Those data are to reasonable approximation, though certainly not perfectly, Gaussian distributed. This work is based on the well-known fact that for Gaussian distributed data, the cross-spectrum completely determines all statistical properties. In particular, for an infinite number of data, all normalized coupling measures at a given frequency are a function of complex coherency. However, it is largely unknown what the functional relations are. We here present those functional relations for six different measures: the weighted phase lag index, the phase lag index, the absolute value and imaginary part of the phase locking value (PLV), power envelope correlation, and power envelope correlation with correction for artifacts of volume conduction. With the exception of PLV, the final results are simple closed form formulas. In an excursion we also discuss differences between short time Fourier transformation and Hilbert transformation for estimations in the frequency domain. We tested in simulations of linear and non-linear dynamical systems and for empirical resting state EEG on sensor level to what extent a model, namely the respective function of coherency, can explain the observed couplings. For empirical data we found that for measures of phase-phase coupling deviations from the model are in general minor, while power envelope correlations systematically deviate from the model for all frequencies. For power envelope correlation with correction for artifacts of volume conduction the model cannot explain the observed couplings at all. We also analyzed power envelope correlation as a function of time and frequency in an event related experiment using a stroop reaction task and found significant event related deviations mostly in the alpha range.
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Affiliation(s)
- Guido Nolte
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Edgar Galindo-Leon
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Zhenghan Li
- Chinese Academy of Science Key Laboratory of Behavioral Science, Institute of Psychology, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Xun Liu
- Chinese Academy of Science Key Laboratory of Behavioral Science, Institute of Psychology, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Andreas K. Engel
- Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Gonzalez-Astudillo J, Cattai T, Bassignana G, Corsi MC, De Vico Fallani F. Network-based brain computer interfaces: principles and applications. J Neural Eng 2020; 18. [PMID: 33147577 DOI: 10.1088/1741-2552/abc760] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 11/04/2020] [Indexed: 12/17/2022]
Abstract
Brain-computer interfaces (BCIs) make possible to interact with the external environment by decoding the mental intention of individuals. BCIs can therefore be used to address basic neuroscience questions but also to unlock a variety of applications from exoskeleton control to neurofeedback (NFB) rehabilitation. In general, BCI usability critically depends on the ability to comprehensively characterize brain functioning and correctly identify the user's mental state. To this end, much of the efforts have focused on improving the classification algorithms taking into account localized brain activities as input features. Despite considerable improvement BCI performance is still unstable and, as a matter of fact, current features represent oversimplified descriptors of brain functioning. In the last decade, growing evidence has shown that the brain works as a networked system composed of multiple specialized and spatially distributed areas that dynamically integrate information. While more complex, looking at how remote brain regions functionally interact represents a grounded alternative to better describe brain functioning. Thanks to recent advances in network science, i.e. a modern field that draws on graph theory, statistical mechanics, data mining and inferential modelling, scientists have now powerful means to characterize complex brain networks derived from neuroimaging data. Notably, summary features can be extracted from these networks to quantitatively measure specific organizational properties across a variety of topological scales. In this topical review, we aim to provide the state-of-the-art supporting the development of a network theoretic approach as a promising tool for understanding BCIs and improve usability.
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Ronconi L, Vitale A, Federici A, Pini E, Molteni M, Casartelli L. Altered neural oscillations and connectivity in the beta band underlie detail-oriented visual processing in autism. Neuroimage Clin 2020; 28:102484. [PMID: 33395975 PMCID: PMC7663221 DOI: 10.1016/j.nicl.2020.102484] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/11/2020] [Accepted: 10/22/2020] [Indexed: 11/21/2022]
Abstract
Sensory and perceptual anomalies may have a major impact on basic cognitive and social skills in humans. Autism Spectrum Disorder (ASD) represents a special perspective to explore this relationship, being characterized by both these features. The present study employed electroencephalography (EEG) to test whether detail-oriented visual perception, a recognized hallmark of ASD, is associated with altered neural oscillations and functional connectivity in the beta frequency band, considering its role in feedback and top-down reentrant signalling in the typical population. Using a visual crowding task, where participants had to discriminate a peripheral target letter surrounded by flankers at different distances, we found that detail-oriented processing in children with ASD, as compared to typically developing peers, could be attributed to anomalous oscillatory activity in the beta band (15-30 Hz), while no differences emerged in the alpha band (8-12 Hz). Altered beta oscillatory response reflected in turn atypical functional connectivity between occipital areas, where the initial stimulus analysis is accomplished, and infero-temporal regions, where objects identity is extracted. Such atypical beta connectivity predicted both ASD symptomatology and their detail-oriented processing. Overall, these results might be explained by an altered feedback connectivity within the visual system, with potential cascade effects in visual scene parsing and higher order functions.
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Affiliation(s)
- Luca Ronconi
- Faculty of Psychology, Vita-Salute San Raffaele University, Milan, Italy; IRCCS San Raffaele Scientific Institute, Milan, Italy; Theoretical and Cognitive Neuroscience Unit, Child Psychopathology Department, Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy.
| | - Andrea Vitale
- Theoretical and Cognitive Neuroscience Unit, Child Psychopathology Department, Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy
| | - Alessandra Federici
- Theoretical and Cognitive Neuroscience Unit, Child Psychopathology Department, Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy; IMT School of Advanced Studies Lucca, Lucca, Italy
| | - Elisa Pini
- Theoretical and Cognitive Neuroscience Unit, Child Psychopathology Department, Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy; Department of Psychology, University of Milano-Bicocca, Milano, Italy
| | - Massimo Molteni
- Child Psychopathology Department, Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy.
| | - Luca Casartelli
- Theoretical and Cognitive Neuroscience Unit, Child Psychopathology Department, Scientific Institute IRCCS Eugenio Medea, Bosisio Parini, Italy
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128
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Ozel P, Karaca A, Olamat A, Akan A, Ozcoban MA, Tan O. Intrinsic Synchronization Analysis of Brain Activity in Obsessive-compulsive Disorders. Int J Neural Syst 2020; 30:2050046. [PMID: 32902344 DOI: 10.1142/s012906572050046x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Obsessive-compulsive disorder (OCD) is one of the neuropsychiatric disorders qualified by intrusive and iterative annoying thoughts and mental attitudes that are activated by these thoughts. In recent studies, advanced signal processing techniques have been favored to diagnose OCD. This research suggests four different measurements; intrinsic phase-locked value, intrinsic coherence, intrinsic synchronization likelihood, and intrinsic visibility graph similarity that quantifies the synchronization level and complexity in electroencephalography (EEG) signals. This intrinsic synchronization is achieved by utilizing Multivariate Empirical Mode Decomposition (MEMD), a data-driven method that resolves nonlinear and nonstationary data into their intrinsic mode functions. Our intrinsic technique in this study demonstrates that MEMD-based synchronization analysis gives us much more detailed knowledge rather than utilizing the synchronization method alone. Furthermore, the nonlinear synchronization method presents more consistent results considering OCD heterogeneity. Statistical evaluation using sample [Formula: see text]-test and [Formula: see text]-test has shown the significance of such new methodology.
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Affiliation(s)
- Pinar Ozel
- Department of Biomedical Engineering, Nevsehir Haci Bektas Veli University, Nevsehir, Turkey
| | - Ali Karaca
- Department of Electrical and Electronics Engineering, Inonu University, Malatya, Turkey
| | - Ali Olamat
- Department of Biomedical Engineering, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Aydin Akan
- Department of Electrical and Electronics Engineering, Izmir University of Economics, Izmir
| | - Mehmet Akif Ozcoban
- Department of Electronic and Automation in Junior Technical College, Gaziantep University, Gaziantep, Turkey
| | - Oguz Tan
- Neuropsychiatry Health, Practice and Research Centre, Uskudar University, Istanbul, Turkey
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129
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Wang C, Laxminarayan S, David Cashmere J, Germain A, Reifman J. Inter-channel phase differences during sleep spindles are altered in Veterans with PTSD. NEUROIMAGE-CLINICAL 2020; 28:102390. [PMID: 32882644 PMCID: PMC7479269 DOI: 10.1016/j.nicl.2020.102390] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/30/2020] [Accepted: 08/17/2020] [Indexed: 01/07/2023]
Abstract
We assessed the spatiotemporal dynamics of slow and fast spindles in PTSD. Inter-channel phase differences during slow spindles were reduced in PTSD. This effect was reproducible across nights and subsamples of the study population. The spatiotemporal dynamics of fast spindles was not altered in PTSD.
Sleep disturbances are common complaints in patients with post-traumatic stress disorder (PTSD). To date, however, objective markers of PTSD during sleep remain elusive. Sleep spindles are distinctive bursts of brain oscillatory activity during non-rapid eye movement (NREM) sleep and have been implicated in sleep protection and sleep-dependent memory processes. In healthy sleep, spindles observed in electroencephalogram (EEG) data are highly synchronized across different regions of the scalp. Here, we aimed to investigate whether the spatiotemporal synchronization patterns between EEG channels during sleep spindles, as quantified by the phase-locking value (PLV) and the mean phase difference (MPD), are altered in PTSD. Using high-density (64-channel) EEG data recorded from 78 combat-exposed Veteran men (31 with PTSD and 47 without PTSD) during two consecutive nights of sleep, we examined group differences in the PLV and MPD for slow (10–13 Hz) and fast (13–16 Hz) spindles separately. To evaluate the reproducibility of our findings, we set apart the first 47 consecutive participants (18 with PTSD) for the initial discovery and reserved the remaining 31 participants (13 with PTSD) for replication analysis. In the discovery analysis, compared to the non-PTSD group, the PTSD group showed smaller MPDs during slow spindles between the frontal and centro-parietal channel pairs on both nights. We obtained reproducible results in the replication analysis in terms of statistical significance and effect size. The PLVs during slow or fast spindles did not significantly differ between groups. The reduced inter-channel phase difference during slow spindles in PTSD may reflect pathological changes in the underlying thalamocortical circuits. This novel finding, if independently validated, may prove useful in developing sleep-focused PTSD diagnostics and interventions.
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Affiliation(s)
- Chao Wang
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, USA; The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., USA
| | - Srinivas Laxminarayan
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, USA; The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., USA
| | - J David Cashmere
- Department of Psychiatry, University of Pittsburgh School of Medicine, USA
| | - Anne Germain
- Department of Psychiatry, University of Pittsburgh School of Medicine, USA
| | - Jaques Reifman
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, USA.
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130
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Qi P, Hu H, Zhu L, Gao L, Yuan J, Thakor N, Bezerianos A, Sun Y. EEG Functional Connectivity Predicts Individual Behavioural Impairment During Mental Fatigue. IEEE Trans Neural Syst Rehabil Eng 2020; 28:2080-2089. [DOI: 10.1109/tnsre.2020.3007324] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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131
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Zhou Z, Cai B, Zhang G, Zhang A, Calhoun VD, Wang YP. Prediction and classification of sleep quality based on phase synchronization related whole-brain dynamic connectivity using resting state fMRI. Neuroimage 2020; 221:117190. [PMID: 32711063 DOI: 10.1016/j.neuroimage.2020.117190] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 07/15/2020] [Accepted: 07/19/2020] [Indexed: 12/15/2022] Open
Abstract
Recently, functional network connectivity (FNC) has been extended from static to dynamic analysis to explore the time-varying functional organization of brain networks. Nowadays, a majority of dynamic FNC (dFNC) analysis frameworks identified recurring FNC patterns with linear correlations based on the amplitude of fMRI time series. However, the brain is a complex dynamical system and phase synchronization provides more informative measures. This paper proposes a novel framework for the prediction/classification of behaviors and cognitions based on the dFNCs derived from phase locking value. When applying to the analysis of fMRI data from Human Connectome Project (HCP), four dFNC states are identified for the study of sleep quality. State 1 exhibits most intense phase synchronization across the whole brain. States 2 and 3 have low and weak connections, respectively. State 4 exhibits strong phase synchronization in intra and inter-connections of somatomotor, visual and cognitive control networks. Through the two-sample t-test, we reveal that for the group with bad sleep quality, state 4 shows decreased phase synchronization within and between networks such as subcortical, auditory, somatomotor and visual, but increased phase synchronization within cognitive control network, and between this network and somatomotor/visual/default-mode/cerebellar networks. The networks with increased phase synchronization in state 4 behave oppositely in state 2. Group differences are absent in state 3, and weak in state 1. We establish a prediction model by linear regression of FNC against sleep quality, and adopt a support vector machine approach for the classification. We compare the performance between conventional FNC and PLV-based dFNC with cross-validation. Results show that the PLV-based dFNC significantly outperforms the conventional FNC in terms of both predictive power and classification accuracy. We also observe that combining static and dynamic features does not significantly improve the classification over using dFNC features alone. Overall, the proposed approach provides a novel means to assess dFNC, which can be used as brain fingerprints to facilitate prediction and classification.
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Affiliation(s)
- Zhongxing Zhou
- Biomedical Engineering Department, Tulane University, New Orleans, LA, United States; Tianjin University, School of Precision Instruments and Optoelectronics Engineering, Tianjin, China
| | - Biao Cai
- Biomedical Engineering Department, Tulane University, New Orleans, LA, United States
| | - Gemeng Zhang
- Biomedical Engineering Department, Tulane University, New Orleans, LA, United States
| | - Aiying Zhang
- Biomedical Engineering Department, Tulane University, New Orleans, LA, United States
| | - Vince D Calhoun
- Tri-institutional Center for Translational Research in Neuroimaging and Data Science (TReNDS) Georgia State University, Georgia Institute of Technology, Emory University, Atlanta, Georgia, United States; Department of Electrical and Computer Engineering, University of New Mexico, Albuquerque, New Mexico, United States
| | - Yu-Ping Wang
- Biomedical Engineering Department, Tulane University, New Orleans, LA, United States.
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132
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Peng Y, Wang Z, Wong CM, Nan W, Rosa A, Xu P, Wan F, Hu Y. Changes of EEG phase synchronization and EOG signals along the use of steady state visually evoked potential-based brain computer interface. J Neural Eng 2020; 17:045006. [DOI: 10.1088/1741-2552/ab933e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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133
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Klein N, Orellana J, Brincat SL, Miller EK, Kass RE. TORUS GRAPHS FOR MULTIVARIATE PHASE COUPLING ANALYSIS. Ann Appl Stat 2020; 14:635-660. [PMID: 36605359 PMCID: PMC9812283 DOI: 10.1214/19-aoas1300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Angular measurements are often modeled as circular random variables, where there are natural circular analogues of moments, including correlation. Because a product of circles is a torus, a d-dimensional vector of circular random variables lies on a d-dimensional torus. For such vectors we present here a class of graphical models, which we call torus graphs, based on the full exponential family with pairwise interactions. The topological distinction between a torus and Euclidean space has several important consequences. Our development was motivated by the problem of identifying phase coupling among oscillatory signals recorded from multiple electrodes in the brain: oscillatory phases across electrodes might tend to advance or recede together, indicating coordination across brain areas. The data analyzed here consisted of 24 phase angles measured repeatedly across 840 experimental trials (replications) during a memory task, where the electrodes were in 4 distinct brain regions, all known to be active while memories are being stored or retrieved. In realistic numerical simulations, we found that a standard pairwise assessment, known as phase locking value, is unable to describe multivariate phase interactions, but that torus graphs can accurately identify conditional associations. Torus graphs generalize several more restrictive approaches that have appeared in various scientific literatures, and produced intuitive results in the data we analyzed. Torus graphs thus unify multivariate analysis of circular data and present fertile territory for future research.
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Affiliation(s)
- Natalie Klein
- Department of Statistics and Data Science, Carnegie Mellon University
| | - Josue Orellana
- Department of Statistics and Data Science, Carnegie Mellon University
| | - Scott L Brincat
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology
| | - Earl K Miller
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology
| | - Robert E Kass
- Department of Statistics and Data Science, Carnegie Mellon University
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134
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Miasnikova A, Perevoznyuk G, Martynova O, Baklushev M. Cross-frequency phase coupling of brain oscillations and relevance attribution as saliency detection in abstract reasoning. Neurosci Res 2020; 166:26-33. [PMID: 32479775 DOI: 10.1016/j.neures.2020.05.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 05/02/2020] [Accepted: 05/25/2020] [Indexed: 11/30/2022]
Abstract
reasoning is associated with the ability to detect relations among objects, ideas, events. It underlies the understanding of other individuals' thoughts and intentions. In natural settings, individuals have to infer relevant associations that have proven to be reliable or precise predictors. Salience theory suggests that the attribution of meaning to stimulus depends on their contingency, saliency, and relevance to adaptation. So far, subjective estimates of relevance have mostly been explored in motivation and implicit learning. Mechanisms underlying formation of associations in abstract thinking with regard to their subjective relevance, or salience, are not clear. Applying novel computational methods, we investigated relevance detection in categorization tasks in 17 healthy individuals. Two models of relevance detection were developed: a conventional one with nouns from the same semantic category, an aberrant one based on an insignificant common feature. Control condition introduced non-related words. The participants were to detect either a relevant principle or an insignificant feature to group presented words. In control condition they inferred that the stimuli were irrelevant to any grouping idea. Cross-frequency phase coupling analysis revealed statistically distinct patterns of synchronization representing search and decision in the models of normal and aberrant relevance detection. Significantly distinct frontotemporal functional networks with central and parietal components in the theta and alpha frequency bands may reflect differences in relevance detection.
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Affiliation(s)
- Aleksandra Miasnikova
- Institute of Higher Nervous Activity and Neurophysiology of Russian Academy of Science, 5A Butlerova St., 117485 Moscow, Russia.
| | - Gleb Perevoznyuk
- MSU, Faculty of Fundamental Medicine, 31-5 Lomonosovsky Prospekt, 117192 Moscow, Russia
| | - Olga Martynova
- Institute of Higher Nervous Activity and Neurophysiology of Russian Academy of Science, 5A Butlerova St., 117485 Moscow, Russia; Centre for Cognition and Decision Making, Institute for Cognitive Neuroscience, National Research University Higher School of Economics, Russian Federation, 20 Myasnitskaya, 101000 Moscow, Russia
| | - Mikhail Baklushev
- Institute of Higher Nervous Activity and Neurophysiology of Russian Academy of Science, 5A Butlerova St., 117485, Moscow, Russia
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135
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Zeev-Wolf M, Levy J, Ebstein RP, Feldman R. Cumulative Risk on Oxytocin-Pathway Genes Impairs Default Mode Network Connectivity in Trauma-Exposed Youth. Front Endocrinol (Lausanne) 2020; 11:335. [PMID: 32528417 PMCID: PMC7256187 DOI: 10.3389/fendo.2020.00335] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/29/2020] [Indexed: 01/08/2023] Open
Abstract
Background: Although the default mode network (DMN) is a core network essential for brain functioning, little is known about its developmental trajectory, particularly on factors associated with its coherence into a functional network. In light of adult studies indicating DMN's susceptibility to stress-related conditions, we examined links between variability on oxytocin-pathway genes and DMN connectivity in youth exposed to chronic war-related trauma Methods: Following a cohort of war-exposed children from early childhood, we imaged the brains of 74 preadolescents (age 11-13 years; 39 war-exposed) during rest using magnetoencephalography (MEG). A cumulative risk index on oxytocin-pathway genes was constructed by combining single nucleotide polymorphisms on five genes previously linked with social deficits and psychopathology; OXTR rs1042778, OXTR rs2254298, OXTRrs53576, CD38 rs3796863, and AVPR1A RS3. Avoidant response to trauma reminders in early childhood and anxiety disorders in late childhood were assessed as predictors of disruptions to DMN theta connectivity. Results: Higher vulnerability on oxytocin-pathway genes predicted greater disruptions to DMN theta connectivity. Avoidant symptoms in early childhood and generalized anxiety disorder in later childhood were related to impaired DMN connectivity. In combination, stress exposure, oxytocin-pathway genes, and stress-related symptoms explained 24.6% of the variance in DMN connectivity, highlighting the significant effect of stress on the maturing brain. Conclusions: Findings are the first to link the oxytocin system and maturation of the DMN, a core system sustaining autobiographical memories, alteration of intrinsic and extrinsic attention, mentalization, and sense of self. Results suggest that oxytocin may buffer the effects of chronic early stress on the DMN, particularly theta rhythms that typify the developing brain.
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Affiliation(s)
- Maor Zeev-Wolf
- Department of Education, Zlotowski Center for Neuroscience, Ben Gurion University of the Negev, Beer Sheva, Israel
| | - Jonathan Levy
- Interdiscilinary Center Herzliya, Baruch Ivcher School of Psychology, Herzliya, Israel
- Department of Neuroscience and Biomedical Engineering, Aalto University, Espoo, Finland
| | - Richard P. Ebstein
- Department of Psychology, National University of Singapore, Singapore, Singapore
| | - Ruth Feldman
- Interdiscilinary Center Herzliya, Baruch Ivcher School of Psychology, Herzliya, Israel
- Child Study Center, Yale University, New Haven, CT, United States
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136
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Gwilt M, Bauer M, Bast T. Frequency- and state-dependent effects of hippocampal neural disinhibition on hippocampal local field potential oscillations in anesthetized rats. Hippocampus 2020; 30:1021-1043. [PMID: 32396678 DOI: 10.1002/hipo.23212] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/09/2020] [Accepted: 04/09/2020] [Indexed: 11/11/2022]
Abstract
Reduced inhibitory GABA function, so-called neural disinhibition, has been implicated in cognitive disorders, including schizophrenia and age-related cognitive decline. We previously showed in rats that hippocampal disinhibition by local microinfusion of the GABA-A receptor antagonist picrotoxin disrupted memory and attention and enhanced hippocampal multi-unit burst firing recorded around the infusion site under isoflurane anesthesia. Here, we analyzed the hippocampal local field potential (LFP) recorded alongside the multi-unit data. We predicted frequency-specific LFP changes, based on previous studies implicating GABA in hippocampal oscillations, with the weight of evidence suggesting that disinhibition would facilitate theta and disrupt gamma oscillations. Using a new semi-automated method based on the kurtosis of the LFP peak-amplitude distribution as well as on amplitude envelope thresholding, we separated three distinct hippocampal LFP states under isoflurane anesthesia: "burst" and "suppression" states-high-amplitude LFP spike bursts and the interspersed low-amplitudeperiods-and a medium-amplitude "continuous" state. The burst state showed greater overall power than suppression and continuous states and higher relative delta/theta power, but lower relative beta/gamma power. The burst state also showed reduced functional connectivity across the hippocampal recording area, especially around theta and beta frequencies. Overall neuronal firing was higher in the burst than the other two states, whereas the proportion of burst firing was higher in burst and continuous states than the suppression state. Disinhibition caused state- and frequency-dependent LFP changes, tending to increase power at lower frequencies (<20 Hz), but to decrease power and connectivity at higher frequencies (>20 Hz) in burst and suppression states. The disinhibition-induced enhancement of multi-unit bursting was also state-dependent, tending to be more pronounced in burst and suppression states than the continuous state. Overall, we characterized three distinct hippocampal LFP states in isoflurane-anesthetized rats. Disinhibition changed hippocampal LFP oscillations in a state- and frequency-dependent way. Moreover, the disinhibition-induced enhancement of multi-unit bursting was also LFP state-dependent.
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Affiliation(s)
- Miriam Gwilt
- School of Psychology and Neuroscience@Nottingham, University of Nottingham, Nottingham, UK
| | - Markus Bauer
- School of Psychology and Neuroscience@Nottingham, University of Nottingham, Nottingham, UK
| | - Tobias Bast
- School of Psychology and Neuroscience@Nottingham, University of Nottingham, Nottingham, UK
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137
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Rogala J, Kublik E, Krauz R, Wróbel A. Resting-state EEG activity predicts frontoparietal network reconfiguration and improved attentional performance. Sci Rep 2020; 10:5064. [PMID: 32193502 PMCID: PMC7081192 DOI: 10.1038/s41598-020-61866-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 03/05/2020] [Indexed: 12/21/2022] Open
Abstract
Mounting evidence indicates that resting-state EEG activity is related to various cognitive functions. To trace physiological underpinnings of this relationship, we investigated EEG and behavioral performance of 36 healthy adults recorded at rest and during visual attention tasks: visual search and gun shooting. All measures were repeated two months later to determine stability of the results. Correlation analyses revealed that within the range of 2–45 Hz, at rest, beta-2 band power correlated with the strength of frontoparietal connectivity and behavioral performance in both sessions. Participants with lower global beta-2 resting-state power (gB2rest) showed weaker frontoparietal connectivity and greater capacity for its modifications, as indicated by changes in phase correlations of the EEG signals. At the same time shorter reaction times and improved shooting accuracy were found, in both test and retest, in participants with low gB2rest compared to higher gB2rest values. We posit that weak frontoparietal connectivity permits flexible network reconfigurations required for improved performance in everyday tasks.
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Affiliation(s)
- Jacek Rogala
- Bioimaging Research Center, World Hearing Center, Institute of Physiology and Pathology of Hearing, Mokra 17 street, Kajetany, 05-830, Nadarzyn, Poland.
| | - Ewa Kublik
- Instytut Biologii Doświadczalnej im. Marcelego Nenckiego, 3 Pasteur Street, 02-093, Warsaw, Poland
| | - Rafał Krauz
- Military University of Technology, Physical Education, 3 gen, Sylwestra Kaliskiego street, 00-908, Warsaw, Poland
| | - Andrzej Wróbel
- Instytut Biologii Doświadczalnej im. Marcelego Nenckiego, 3 Pasteur Street, 02-093, Warsaw, Poland.,Department of Epistemology, Institute of Philosophy, University of Warsaw, 3 Krakowskie Przedmiescie street, 00-927, Warszawa, Poland
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138
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Gaudet I, Hüsser A, Vannasing P, Gallagher A. Functional Brain Connectivity of Language Functions in Children Revealed by EEG and MEG: A Systematic Review. Front Hum Neurosci 2020; 14:62. [PMID: 32226367 PMCID: PMC7080982 DOI: 10.3389/fnhum.2020.00062] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 02/10/2020] [Indexed: 01/29/2023] Open
Abstract
The development of language functions is of great interest to neuroscientists, as these functions are among the fundamental capacities of human cognition. For many years, researchers aimed at identifying cerebral correlates of language abilities. More recently, the development of new data analysis tools has generated a shift toward the investigation of complex cerebral networks. In 2015, Weiss-Croft and Baldeweg published a very interesting systematic review on the development of functional language networks, explored through the use of functional magnetic resonance imaging (fMRI). Compared to fMRI and because of their excellent temporal resolution, magnetoencephalography (MEG) and electroencephalography (EEG) provide different and important information on brain activity. Both therefore constitute crucial neuroimaging techniques for the investigation of the maturation of functional language brain networks. The main objective of this systematic review is to provide a state of knowledge on the investigation of language-related cerebral networks in children, through the use of EEG and MEG, as well as a detailed portrait of relevant MEG and EEG data analysis methods used in that specific research context. To do so, we have summarized the results and systematically compared the methodological approach of 24 peer-reviewed EEG or MEG scientific studies that included healthy children and children with or at high risk of language disabilities, from birth up to 18 years of age. All included studies employed functional and effective connectivity measures, such as coherence, phase locking value, and Phase Slope Index, and did so using different experimental paradigms (e.g., at rest or during language-related tasks). This review will provide more insight into the use of EEG and MEG for the study of language networks in children, contribute to the current state of knowledge on the developmental path of functional connectivity in language networks during childhood and adolescence, and finally allow future studies to choose the most appropriate type of connectivity analysis.
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Affiliation(s)
- Isabelle Gaudet
- Laboratoire d'imagerie optique en neurodéveloppement (LIONLAB), Sainte-Justine University Hospital Research Center, Montréal, QC, Canada.,Department of Psychology, Université de Montréal, Montréal, QC, Canada
| | - Alejandra Hüsser
- Laboratoire d'imagerie optique en neurodéveloppement (LIONLAB), Sainte-Justine University Hospital Research Center, Montréal, QC, Canada.,Department of Psychology, Université de Montréal, Montréal, QC, Canada
| | - Phetsamone Vannasing
- Laboratoire d'imagerie optique en neurodéveloppement (LIONLAB), Sainte-Justine University Hospital Research Center, Montréal, QC, Canada
| | - Anne Gallagher
- Laboratoire d'imagerie optique en neurodéveloppement (LIONLAB), Sainte-Justine University Hospital Research Center, Montréal, QC, Canada.,Department of Psychology, Université de Montréal, Montréal, QC, Canada
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139
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Fischer P, Lipski WJ, Neumann WJ, Turner RS, Fries P, Brown P, Richardson RM. Movement-related coupling of human subthalamic nucleus spikes to cortical gamma. eLife 2020; 9:51956. [PMID: 32159515 PMCID: PMC7096181 DOI: 10.7554/elife.51956] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 03/11/2020] [Indexed: 11/13/2022] Open
Abstract
Cortico-basal ganglia interactions continuously shape the way we move. Ideas about how this circuit works are based largely on models those consider only firing rate as the mechanism of information transfer. A distinct feature of neural activity accompanying movement, however, is increased motor cortical and basal ganglia gamma synchrony. To investigate the relationship between neuronal firing in the basal ganglia and cortical gamma activity during movement, we analysed human ECoG and subthalamic nucleus (STN) unit activity during hand gripping. We found that fast reaction times were preceded by enhanced STN spike-to-cortical gamma phase coupling, indicating a role in motor preparation. Importantly, increased gamma phase coupling occurred independent of changes in mean STN firing rates, and the relative timing of STN spikes was offset by half a gamma cycle for ipsilateral vs. contralateral movements, indicating that relative spike timing is as relevant as firing rate for understanding cortico-basal ganglia information transfer.
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Affiliation(s)
- Petra Fischer
- Medical Research Council Brain Network Dynamics Unit, University of Oxford, Oxford, United Kingdom.,Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - Witold J Lipski
- Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, United States
| | - Wolf-Julian Neumann
- Department of Neurology, Campus Mitte, Charite - Universitaetsmedizin Berlin, Berlin, Germany
| | - Robert S Turner
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, United States.,Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, United States
| | - Pascal Fries
- Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, Frankfurt, Germany.,Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands
| | - Peter Brown
- Medical Research Council Brain Network Dynamics Unit, University of Oxford, Oxford, United Kingdom.,Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, United Kingdom
| | - R Mark Richardson
- Department of Neurosurgery, Massachusetts General Hospital, Boston, United States.,Harvard Medical School, Boston, United States
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140
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Czeszumski A, Eustergerling S, Lang A, Menrath D, Gerstenberger M, Schuberth S, Schreiber F, Rendon ZZ, König P. Hyperscanning: A Valid Method to Study Neural Inter-brain Underpinnings of Social Interaction. Front Hum Neurosci 2020; 14:39. [PMID: 32180710 PMCID: PMC7059252 DOI: 10.3389/fnhum.2020.00039] [Citation(s) in RCA: 175] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 01/27/2020] [Indexed: 01/11/2023] Open
Abstract
Social interactions are a crucial part of human life. Understanding the neural underpinnings of social interactions is a challenging task that the hyperscanning method has been trying to tackle over the last two decades. Here, we review the existing literature and evaluate the current state of the hyperscanning method. We review the type of methods (fMRI, M/EEG, and fNIRS) that are used to measure brain activity from more than one participant simultaneously and weigh their pros and cons for hyperscanning. Further, we discuss different types of analyses that are used to estimate brain networks and synchronization. Lastly, we present results of hyperscanning studies in the context of different cognitive functions and their relations to social interactions. All in all, we aim to comprehensively present methods, analyses, and results from the last 20 years of hyperscanning research.
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Affiliation(s)
- Artur Czeszumski
- Institute of Cognitive Science, Universität Osnabrück, Osnabrück, Germany
| | - Sara Eustergerling
- Institute of Cognitive Science, Universität Osnabrück, Osnabrück, Germany
| | - Anne Lang
- Institute of Cognitive Science, Universität Osnabrück, Osnabrück, Germany
| | - David Menrath
- Institute of Cognitive Science, Universität Osnabrück, Osnabrück, Germany
| | | | - Susanne Schuberth
- Institute of Cognitive Science, Universität Osnabrück, Osnabrück, Germany
| | - Felix Schreiber
- Institute of Cognitive Science, Universität Osnabrück, Osnabrück, Germany
| | | | - Peter König
- Institute of Cognitive Science, Universität Osnabrück, Osnabrück, Germany.,Institut für Neurophysiologie und Pathophysiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
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141
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Moon K, Guan Y, Li LKB, Kim KT. Mutual synchronization of two flame-driven thermoacoustic oscillators: Dissipative and time-delayed coupling effects. CHAOS (WOODBURY, N.Y.) 2020; 30:023110. [PMID: 32113251 DOI: 10.1063/1.5126765] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 01/13/2020] [Indexed: 06/10/2023]
Abstract
Low-emissions can-annular gas turbines are prone to develop low-frequency self-excited thermoacoustic oscillations. Such oscillations arise from the coupling between adjacent combustors and can increase wear and thermal stresses. In this experimental study, we explore the mutual synchronization of two thermoacoustic oscillators (i.e., two model combustors) interacting via dissipative and time-delayed coupling, as introduced via a cross-talk section. Unlike most previous studies, our study makes use of a turbulent lean-premixed flame in each combustor, bringing the system configuration closer to that of practical gas turbines. Using stationary and transient measurements, we examine the effect of the cross-talk diameter and length so as to gain insight into the effect of dissipative and time-delayed coupling. We find that strengthening the dissipative coupling promotes mutual synchronization, but that weakening the dissipative coupling leads to weakly coupled or desynchronized oscillations. On operating the two combustors at different conditions, we find a significant reduction in their overall oscillation amplitude for some coupling conditions. On varying the combustor length and examining the transient response, we find elaborate changes in the pressure-heat-release-rate coupling, spontaneous mode transitions between coupled thermoacoustic modes, and the emergence of a rhomboid structure in the phase plane owing to the coexistence of in-phase and out-of-phase synchronization. In the combustion community, these two types of synchronization are known to be associated with push-push modes and push-pull modes. These findings offer new insight into the mutual synchronization of low-frequency, self-excited thermoacoustic oscillations in can-annular gas turbines, paving the way for the development of improved control strategies.
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Affiliation(s)
- Kihun Moon
- Department of Aerospace Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Yu Guan
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Larry K B Li
- Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong
| | - Kyu Tae Kim
- Department of Aerospace Engineering, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea
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142
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Computational modelling in source space from scalp EEG to inform presurgical evaluation of epilepsy. Clin Neurophysiol 2019; 131:225-234. [PMID: 31812920 PMCID: PMC6941468 DOI: 10.1016/j.clinph.2019.10.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/26/2019] [Accepted: 10/26/2019] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The effectiveness of intracranial electroencephalography (iEEG) to inform epilepsy surgery depends on where iEEG electrodes are implanted. This decision is informed by noninvasive recording modalities such as scalp EEG. Herein we propose a framework to interrogate scalp EEG and determine epilepsy lateralization to aid in electrode implantation. METHODS We use eLORETA to map source activities from seizure epochs recorded from scalp EEG and consider 15 regions of interest (ROIs). Functional networks are then constructed using the phase-locking value and studied using a mathematical model. By removing different ROIs from the network and simulating their impact on the network's ability to generate seizures in silico, the framework provides predictions of epilepsy lateralization. We consider 15 individuals from the EPILEPSIAE database and study a total of 62 seizures. Results were assessed by taking into account actual intracranial implantations and surgical outcome. RESULTS The framework provided potentially useful information regarding epilepsy lateralization in 12 out of the 15 individuals (p=0.02, binomial test). CONCLUSIONS Our results show promise for the use of this framework to better interrogate scalp EEG to determine epilepsy lateralization. SIGNIFICANCE The framework may aid clinicians in the decision process to define where to implant electrodes for intracranial monitoring.
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143
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Rossini P, Di Iorio R, Bentivoglio M, Bertini G, Ferreri F, Gerloff C, Ilmoniemi R, Miraglia F, Nitsche M, Pestilli F, Rosanova M, Shirota Y, Tesoriero C, Ugawa Y, Vecchio F, Ziemann U, Hallett M. Methods for analysis of brain connectivity: An IFCN-sponsored review. Clin Neurophysiol 2019; 130:1833-1858. [DOI: 10.1016/j.clinph.2019.06.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 05/08/2019] [Accepted: 06/18/2019] [Indexed: 01/05/2023]
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144
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Posterior Hippocampal Spindle Ripples Co-occur with Neocortical Theta Bursts and Downstates-Upstates, and Phase-Lock with Parietal Spindles during NREM Sleep in Humans. J Neurosci 2019; 39:8949-8968. [PMID: 31530646 DOI: 10.1523/jneurosci.2858-18.2019] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 06/26/2019] [Accepted: 07/13/2019] [Indexed: 01/26/2023] Open
Abstract
Human anterior and posterior hippocampus (aHC, pHC) differ in connectivity and behavioral correlates. Here we report physiological differences in humans of both sexes. During NREM sleep, the human hippocampus generates sharpwave ripples (SWRs) similar to those which in rodents mark memory replay. We show that while pHC generates SWRs, it also generates approximately as many spindle ripples (SSR: ripples phase-locked to local spindles). In contrast, SSRs are rare in aHC. Like SWRs, SSRs often co-occur with neocortical theta bursts (TBs), downstates (DSs), sleep spindles (SSs), and upstates (USs), which coordinate cortico-hippocampal interactions and facilitate consolidation in rodents. SWRs co-occur with these waves in widespread cortical areas, especially frontocentral. These waves typically occur in the sequence TB-DS-SS-US, with SWRs usually occurring before SS-US. In contrast, SSRs occur ∼350 ms later, with a strong preference for co-occurrence with posterior-parietal SSs. pHC-SSs were strongly phase-locked with parietal-SSs, and pHC-SSRs were phase-coupled with pHC-SSs and parietal-SSs. Human SWRs (and associated replay events, if any) are separated by ∼5 s on average, whereas ripples on successive SSR peaks are separated by only ∼80 ms. These distinctive physiological properties of pHC-SSR enable an alternative mechanism for hippocampal engagement with neocortex.SIGNIFICANCE STATEMENT Rodent hippocampal neurons replay waking events during sharpwave ripples (SWRs) in NREM sleep, facilitating memory transfer to a permanent cortical store. We show that human anterior hippocampus also produces SWRs, but spindle ripples predominate in posterior. Whereas SWRs typically occur as cortex emerges from inactivity, spindle ripples typically occur at peak cortical activity. Furthermore, posterior hippocampal spindle ripples are tightly coupled to posterior parietal locations activated by conscious recollection. Finally, multiple spindle ripples can recur within a second, whereas SWRs are separated by ∼5 s. The human posterior hippocampus is considered homologous to rodent dorsal hippocampus, which is thought to be specialized for consolidation of specific memory details. We speculate that these distinct physiological characteristics of posterior hippocampal spindle ripples may support a related function in humans.
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145
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Velarde OM, Urdapilleta E, Mato G, Dellavale D. Bifurcation structure determines different phase-amplitude coupling patterns in the activity of biologically plausible neural networks. Neuroimage 2019; 202:116031. [PMID: 31330244 DOI: 10.1016/j.neuroimage.2019.116031] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 07/10/2019] [Accepted: 07/16/2019] [Indexed: 12/15/2022] Open
Abstract
Phase-amplitude cross frequency coupling (PAC) is a rather ubiquitous phenomenon that has been observed in a variety of physical domains; however, the mechanisms underlying the emergence of PAC and its functional significance in the context of neural processes are open issues under debate. In this work we analytically demonstrate that PAC phenomenon naturally emerges in mean-field models of biologically plausible networks, as a signature of specific bifurcation structures. The proposed analysis, based on bifurcation theory, allows the identification of the mechanisms underlying oscillatory dynamics that are essentially different in the context of PAC. Specifically, we found that two PAC classes can coexist in the complex dynamics of the analyzed networks: 1) harmonic PAC which is an epiphenomenon of the nonsinusoidal waveform shape characterized by the linear superposition of harmonically related spectral components, and 2) nonharmonic PAC associated with "true" coupled oscillatory dynamics with independent frequencies elicited by a secondary Hopf bifurcation and mechanisms involving periodic excitation/inhibition (PEI) of a network population. Importantly, these two PAC types have been experimentally observed in a variety of neural architectures confounding traditional parametric and nonparametric PAC metrics, like those based on linear filtering or the waveform shape analysis, due to the fact that these methods operate on a single one-dimensional projection of an intrinsically multidimensional system dynamics. We exploit the proposed tools to study the functional significance of the PAC phenomenon in the context of Parkinson's disease (PD). Our results show that pathological slow oscillations (e.g. β band) and nonharmonic PAC patterns emerge from dissimilar underlying mechanisms (bifurcations) and are associated to the competition of different BG-thalamocortical loops. Thus, this study provides theoretical arguments that demonstrate that nonharmonic PAC is not an epiphenomenon related to the pathological β band oscillations, thus supporting the experimental evidence about the relevance of PAC as a potential biomarker of PD.
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Affiliation(s)
- Osvaldo Matías Velarde
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica (CNEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCUYO), Av. E. Bustillo 9500, R8402AGP, San Carlos de Bariloche, Río Negro, Argentina
| | - Eugenio Urdapilleta
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica (CNEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCUYO), Av. E. Bustillo 9500, R8402AGP, San Carlos de Bariloche, Río Negro, Argentina
| | - Germán Mato
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica (CNEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCUYO), Av. E. Bustillo 9500, R8402AGP, San Carlos de Bariloche, Río Negro, Argentina.
| | - Damián Dellavale
- Centro Atómico Bariloche and Instituto Balseiro, Comisión Nacional de Energía Atómica (CNEA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Cuyo (UNCUYO), Av. E. Bustillo 9500, R8402AGP, San Carlos de Bariloche, Río Negro, Argentina.
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146
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Training state and performance evaluation of working memory based on task-related EEG. Biomed Signal Process Control 2019. [DOI: 10.1016/j.bspc.2019.03.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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147
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Gong A, Liu J, Lu L, Wu G, Jiang C, Fu Y. Characteristic differences between the brain networks of high-level shooting athletes and non-athletes calculated using the phase-locking value algorithm. Biomed Signal Process Control 2019. [DOI: 10.1016/j.bspc.2019.02.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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148
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Duc NT, Lee B. Microstate functional connectivity in EEG cognitive tasks revealed by a multivariate Gaussian hidden Markov model with phase locking value. J Neural Eng 2019; 16:026033. [DOI: 10.1088/1741-2552/ab0169] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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149
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Wang Y, Xie P, Zhou S, Wang X, Yuan Y. Low-intensity pulsed ultrasound modulates multi-frequency band phase synchronization between LFPs and EMG in mice. J Neural Eng 2019; 16:026036. [PMID: 30780150 DOI: 10.1088/1741-2552/ab0879] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Low-intensity pulsed ultrasound stimulation (LIPUS) targeted to the mouse motor cortex can simultaneously induce local field potentials (LFPs) and electromyogram (EMG) responses. However, the functional coupling relationship between LFP and EMG signals has not been elucidated to date. This study aimed to investigate the phase synchronization between LFP and EMG signals induced by LIPUS over the mouse motor cortex. APPROACH LIPUS at 500 kHz with varied sonication intensities and duty cycles (DCs), was delivered to the mouse motor cortex. LFPs of the motor cortex and EMG responses of the tail were simultaneously recorded during LIPUS. We then evaluated two control groups using the same experimental parameters, but changed the position of EMG recording to the hind leg and the ultrasound stimulus target to the primary visual cortex. The phase synchronization between LFPs and EMG signals was evaluated by performing a phase locking value (PLV) analysis in the time-frequency domain and was compared across specific frequency bands. MAIN RESULTS The results showed that LIPUS increased the phase synchronization in a broad frequency band (5-150 Hz), and the maximum duration of the increased PLV was stable at approximately 200 ms. It is worth noting that the sonication parameters directly affected the time-frequency domain distribution of cortico-muscular synchronization. Specifically, significant alpha and beta synchronization appeared at 0.2 and 0.4 W cm-2 I sppa stimulation, while gamma synchronization occurred at 0.8 and 1.1 W cm-2 I sppa stimulation. The synchronization in all frequency bands apparently increased at 30% DC. Beta synchronization weakened when the DC was less than 30%. Furthermore, no significant phase synchronization was observed in the two control groups. SIGNIFICANCE Considering the close association between specific motor function and cortical-muscular synchronization in different frequency bands, we suggest that LIPUS over the motor cortex could selectively modulate motor function via different sonication parameters. Additionally, the phase synchronization between LFPs and EMG might be an invaluable index for assessing the ultrasonic effect on the motor system, which could be used in future clinical research to optimize ultrasound parameters. Thus, this study provides new insight into evaluating the neuromodulatory effects of ultrasound on motor function, thereby supporting the therapeutic application of ultrasound in neurological disorders characterized by motor deficits.
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Affiliation(s)
- Yibo Wang
- Institute of Electric Engineering, Yanshan University, Qinhuangdao, Hebei 066004, People's Republic of China
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150
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Gamma Oscillations in the Basolateral Amygdala: Biophysical Mechanisms and Computational Consequences. eNeuro 2019; 6:eN-NWR-0388-18. [PMID: 30805556 PMCID: PMC6361623 DOI: 10.1523/eneuro.0388-18.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 12/12/2018] [Accepted: 12/22/2018] [Indexed: 01/04/2023] Open
Abstract
The basolateral nucleus of the amygdala (BL) is thought to support numerous emotional behaviors through specific microcircuits. These are often thought to be comprised of feedforward networks of principal cells (PNs) and interneurons. Neither well-understood nor often considered are recurrent and feedback connections, which likely engender oscillatory dynamics within BL. Indeed, oscillations in the gamma frequency range (40 − 100 Hz) are known to occur in the BL, and yet their origin and effect on local circuits remains unknown. To address this, we constructed a biophysically and anatomically detailed model of the rat BL and its local field potential (LFP) based on the physiological and anatomical literature, along with in vivo and in vitro data we collected on the activities of neurons within the rat BL. Remarkably, the model produced intermittent gamma oscillations (∼50 − 70 Hz) whose properties matched those recorded in vivo, including their entrainment of spiking. BL gamma-band oscillations were generated by the intrinsic circuitry, depending upon reciprocal interactions between PNs and fast-spiking interneurons (FSIs), while connections within these cell types affected the rhythm’s frequency. The model allowed us to conduct experimentally impossible tests to characterize the synaptic and spatial properties of gamma. The entrainment of individual neurons to gamma depended on the number of afferent connections they received, and gamma bursts were spatially restricted in the BL. Importantly, the gamma rhythm synchronized PNs and mediated competition between ensembles. Together, these results indicate that the recurrent connectivity of BL expands its computational and communication repertoire.
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