1
|
Wagner AR, Kobel MJ, Tajino J, Merfeld DM. Improving self-motion perception and balance through roll tilt perceptual training. J Neurophysiol 2022; 128:619-633. [PMID: 35894439 PMCID: PMC9448335 DOI: 10.1152/jn.00092.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 07/18/2022] [Accepted: 07/23/2022] [Indexed: 11/22/2022] Open
Abstract
The present study aimed to determine if a vestibular perceptual learning intervention could improve roll tilt self-motion perception and balance performance. Two intervention groups (n = 10 each) performed 1,300 trials of roll tilt at either 0.5 Hz (2 s/motion) or 0.2 Hz (5 s/motion) distributed over 5 days; each intervention group was provided feedback (correct/incorrect) after each trial. Roll tilt perceptual thresholds, measured using 0.2-, 0.5-, and 1-Hz stimuli, as well as quiet stance postural sway, were measured on day 1 and day 6 of the study. The control group (n = 10) who performed no perceptual training, showed stable 0.2-Hz (+1.48%, P > 0.99), 0.5-Hz (-4.0%, P > 0.99), and 1-Hz (-17.48%, P = 0.20) roll tilt thresholds. The 0.2-Hz training group demonstrated significant improvements in both 0.2-Hz (-23.77%, P = 0.003) and 0.5-Hz (-22.2%, P = 0.03) thresholds. The 0.5-Hz training group showed a significant improvement in 0.2-Hz thresholds (-19.13%, P = 0.029), but not 0.5-Hz thresholds (-17.68%, P = 0.052). Neither training group improved significantly at the untrained 1-Hz frequency (P > 0.05). In addition to improvements in perceptual precision, the 0.5-Hz training group showed a decrease in sway when measured during "eyes open, on foam" (dz = 0.57, P = 0.032) and "eyes closed, on foam" (dz = 2.05, P < 0.001) quiet stance balance tasks. These initial data suggest that roll tilt perception can be improved with less than 5 h of training and that vestibular perceptual training may contribute to a reduction in subclinical postural instability.NEW & NOTEWORTHY Roll tilt vestibular perceptual thresholds, an assay of vestibular noise, were recently found to correlate with postural sway. We therefore hypothesized that roll tilt perceptual training would yield improvements in both perceptual precision and balance. Our data show that roll tilt perceptual thresholds and quiet stance postural sway can be significantly improved after less than 5 h of roll tilt perceptual training, supporting the hypothesis that vestibular noise contributes to increased postural sway.
Collapse
Affiliation(s)
- Andrew R Wagner
- Department of Otolaryngology-Head & Neck Surgery, Ohio State University Wexner Medical Center, Columbus, Ohio
- School of Health and Rehabilitation Sciences, Ohio State University, Columbus, Ohio
| | - Megan J Kobel
- Department of Otolaryngology-Head & Neck Surgery, Ohio State University Wexner Medical Center, Columbus, Ohio
- Department of Speech and Hearing Science, Ohio State University, Columbus, Ohio
| | - Junichi Tajino
- Department of Otolaryngology-Head & Neck Surgery, Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Daniel M Merfeld
- Department of Otolaryngology-Head & Neck Surgery, Ohio State University Wexner Medical Center, Columbus, Ohio
- School of Health and Rehabilitation Sciences, Ohio State University, Columbus, Ohio
- Department of Speech and Hearing Science, Ohio State University, Columbus, Ohio
- Department of Biomedical Engineering, Ohio State University, Columbus, Ohio
| |
Collapse
|
2
|
Goodman AM, Wheelock MD, Harnett NG, Davis ES, Mrug S, Deshpande G, Knight DC. Stress-Induced Changes in Effective Connectivity During Regulation of the Emotional Response to Threat. Brain Connect 2022; 12:629-638. [PMID: 34541896 PMCID: PMC9634990 DOI: 10.1089/brain.2021.0062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: Stress-related disruption of emotion regulation appears to involve the prefrontal cortex (PFC) and amygdala. However, the interactions between brain regions that mediate stress-induced changes in emotion regulation remain unclear. The present study builds upon prior work that assessed stress-induced changes in the neurobehavioral response to threat by investigating effective connectivity between these brain regions. Methods: Participants completed the Montreal Imaging Stress Task followed by a Pavlovian fear conditioning procedure during functional magnetic resonance imaging. Stress ratings and psychophysiological responses were used to assess stress reactivity. Effective connectivity during fear conditioning was identified using multivariate autoregressive modeling. Effective connectivity values were calculated during threat presentations that were either predictable (preceded by a warning cue) or unpredictable (no warning cue). Results: A neural hub within the dorsomedial PFC (dmPFC) showed greater effective connectivity to other PFC regions, inferior parietal lobule, insula, and amygdala during predictable than unpredictable threat. The dmPFC also showed greater connectivity to different dorsolateral PFC and amygdala regions during unpredictable than predictable threat. Stress ratings varied with connectivity differences from the dmPFC to the amygdala. Connectivity from dmPFC to amygdala was greater in general during unpredictable than predictable threat, however, this connectivity increased during predictable compared with unpredictable threat as stress reactivity increased. Conclusions: Our findings suggest that acute stress disrupts connectivity underlying top-down emotion regulation of the threat response. Furthermore, increased connectivity between the dmPFC and amygdala may play a critical role in stress-induced changes in the emotional response to threat. Impact statement The present study builds upon prior work that assessed stress-induced changes in the human neurobehavioral response to threat by demonstrating that increased top-down connectivity from the dorsomedial prefrontal cortex to the amygdala varies with individual differences in stress reactivity. These findings provide novel evidence in humans of stress-induced disruption of a specific top-down corticolimbic circuit during active emotion regulation processes, which may play a causal role in the long-term effects of chronic or excessive stress exposure.
Collapse
Affiliation(s)
- Adam M. Goodman
- Department of Psychology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Muriah D. Wheelock
- Department of Psychology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Nathaniel G. Harnett
- Department of Psychology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Elizabeth S. Davis
- Department of Psychology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Sylvie Mrug
- Department of Psychology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Gopikrishna Deshpande
- Auburn University MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama, USA
- Department of Psychological Sciences, Auburn University, Auburn, Alabama, USA
- Alabama Advanced Imaging Consortium, University of Alabama Birmingham, Alabama, USA
- Center for Neuroscience, Auburn University, Auburn, Alabama, USA
- School of Psychology, Capital Normal University, Beijing, China
- Key Laboratory for Learning and Cognition, Capital Normal University, Beijing, China
- Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bangalore, India
| | - David C. Knight
- Department of Psychology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| |
Collapse
|
3
|
Gilson M, Zamora-López G, Pallarés V, Adhikari MH, Senden M, Campo AT, Mantini D, Corbetta M, Deco G, Insabato A. Model-based whole-brain effective connectivity to study distributed cognition in health and disease. Netw Neurosci 2020; 4:338-373. [PMID: 32537531 PMCID: PMC7286310 DOI: 10.1162/netn_a_00117] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 12/02/2019] [Indexed: 12/12/2022] Open
Abstract
Neuroimaging techniques are now widely used to study human cognition. The functional associations between brain areas have become a standard proxy to describe how cognitive processes are distributed across the brain network. Among the many analysis tools available, dynamic models of brain activity have been developed to overcome the limitations of original connectivity measures such as functional connectivity. This goes in line with the many efforts devoted to the assessment of directional interactions between brain areas from the observed neuroimaging activity. This opinion article provides an overview of our model-based whole-brain effective connectivity to analyze fMRI data, while discussing the pros and cons of our approach with respect to other established approaches. Our framework relies on the multivariate Ornstein-Uhlenbeck (MOU) process and is thus referred to as MOU-EC. Once tuned, the model provides a directed connectivity estimate that reflects the dynamical state of BOLD activity, which can be used to explore cognition. We illustrate this approach using two applications on task-evoked fMRI data. First, as a connectivity measure, MOU-EC can be used to extract biomarkers for task-specific brain coordination, understood as the patterns of areas exchanging information. The multivariate nature of connectivity measures raises several challenges for whole-brain analysis, for which machine-learning tools present some advantages over statistical testing. Second, we show how to interpret changes in MOU-EC connections in a collective and model-based manner, bridging with network analysis. Our framework provides a comprehensive set of tools that open exciting perspectives to study distributed cognition, as well as neuropathologies.
Collapse
Affiliation(s)
- Matthieu Gilson
- Center for Brain and Cognition and Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
| | - Gorka Zamora-López
- Center for Brain and Cognition and Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
| | - Vicente Pallarés
- Center for Brain and Cognition and Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
| | - Mohit H. Adhikari
- Center for Brain and Cognition and Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
| | - Mario Senden
- Department of Cognitive Neuroscience, University of Maastricht, Maastricht, The Netherlands
| | | | - Dante Mantini
- Neuroplasticity and Motor Control Research Group, KU Leuven, Leuven, Belgium
- Brain Imaging and Neural Dynamics Research Group, IRCCS San Camillo Hospital, Venice, Italy
| | - Maurizio Corbetta
- Department of Neuroscience, Venetian Institute of Molecular Medicine (VIMM) and Padova Neuroscience Center (PNC), University of Padua, Italy
- Department of Neurology, Radiology, and Neuroscience, Washington University School of Medicine, St. Louis, MO, USA
| | - Gustavo Deco
- Center for Brain and Cognition and Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
- Institució Catalana de la Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Andrea Insabato
- Institut de Neurosciences de la Timone, CNRS, Marseille, France
| |
Collapse
|
4
|
Deshpande G, Jia H. Multi-Level Clustering of Dynamic Directional Brain Network Patterns and Their Behavioral Relevance. Front Neurosci 2020; 13:1448. [PMID: 32116487 PMCID: PMC7017718 DOI: 10.3389/fnins.2019.01448] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Accepted: 12/27/2019] [Indexed: 11/18/2022] Open
Abstract
Dynamic functional connectivity (DFC) obtained from resting state functional magnetic resonance imaging (fMRI) data has been shown to provide novel insights into brain function which may be obscured by static functional connectivity (SFC). Further, DFC, and by implication how different brain regions may engage or disengage with each other over time, has been shown to be behaviorally relevant and more predictive than SFC of behavioral performance and/or diagnostic status. DFC is not a directional entity and may capture neural synchronization. However, directional interactions between different brain regions is another putative mechanism by which neural populations communicate. Accordingly, static effective connectivity (SEC) has been explored as a means of characterizing such directional interactions. But investigation of its dynamic counterpart, i.e., dynamic effective connectivity (DEC), is still in its infancy. Of particular note are methodological insufficiencies in identifying DEC configurations that are reproducible across time and subjects as well as a lack of understanding of the behavioral relevance of DEC obtained from resting state fMRI. In order to address these issues, we employed a dynamic multivariate autoregressive (MVAR) model to estimate DEC. The method was first validated using simulations and then applied to resting state fMRI data obtained in-house (N = 21), wherein we performed dynamic clustering of DEC matrices across multiple levels [using adaptive evolutionary clustering (AEC)] – spatial location, time, and subjects. We observed a small number of directional brain network configurations alternating between each other over time in a quasi-stable manner akin to brain microstates. The dominant and consistent DEC network patterns involved several regions including inferior and mid temporal cortex, motor and parietal cortex, occipital cortex, as well as part of frontal cortex. The functional relevance of these DEC states were determined using meta-analyses and pertained mainly to memory and emotion, but also involved execution and language. Finally, a larger cohort of resting-state fMRI and behavioral data from the Human Connectome Project (HCP) (N = 232, Q1–Q3 release) was used to demonstrate that metrics derived from DEC can explain larger variance in 70 behaviors across different domains (alertness, cognition, emotion, and personality traits) compared to SEC in healthy individuals.
Collapse
Affiliation(s)
- Gopikrishna Deshpande
- Department of Electrical and Computer Engineering, AU MRI Research Center, Auburn University, Auburn, AL, United States.,Department of Psychology, Auburn University, Auburn, AL, United States.,Center for Neuroscience, Auburn University, Auburn, AL, United States.,Center for Health Ecology and Equity Research, Auburn, AL, United States.,Alabama Advanced Imaging Consortium, Birmingham, AL, United States.,Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bengaluru, India.,School of Psychology, Capital Normal University, Beijing, China.,Key Laboratory for Learning and Cognition, Capital Normal University, Beijing, China
| | - Hao Jia
- Department of Automation, College of Information Engineering, Taiyuan University of Technology, Taiyuan, China
| |
Collapse
|
5
|
Bielczyk NZ, Llera A, Buitelaar JK, Glennon JC, Beckmann CF. Increasing robustness of pairwise methods for effective connectivity in magnetic resonance imaging by using fractional moment series of BOLD signal distributions. Netw Neurosci 2019; 3:1009-1037. [PMID: 31637336 PMCID: PMC6779268 DOI: 10.1162/netn_a_00099] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 06/03/2019] [Indexed: 12/20/2022] Open
Abstract
Estimating causal interactions in the brain from functional magnetic resonance imaging (fMRI) data remains a challenging task. Multiple studies have demonstrated that all current approaches to determine direction of connectivity perform poorly when applied to synthetic fMRI datasets. Recent advances in this field include methods for pairwise inference, which involve creating a sparse connectome in the first step, and then using a classifier in order to determine the directionality of connection between every pair of nodes in the second step. In this work, we introduce an advance to the second step of this procedure, by building a classifier based on fractional moments of the BOLD distribution combined into cumulants. The classifier is trained on datasets generated under the dynamic causal modeling (DCM) generative model. The directionality is inferred based on statistical dependencies between the two-node time series, for example, by assigning a causal link from time series of low variance to time series of high variance. Our approach outperforms or performs as well as other methods for effective connectivity when applied to the benchmark datasets. Crucially, it is also more resilient to confounding effects such as differential noise level across different areas of the connectome.
Collapse
Affiliation(s)
- Natalia Z. Bielczyk
- Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
- Department of Cognitive Neuroscience, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Alberto Llera
- Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
- Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Jan K. Buitelaar
- Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
- Department of Cognitive Neuroscience, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Jeffrey C. Glennon
- Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
- Department of Cognitive Neuroscience, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Christian F. Beckmann
- Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
- Department of Cognitive Neuroscience, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
- Radboud University Nijmegen, Nijmegen, the Netherlands
- Oxford Centre for Functional MRI of the Brain, University of Oxford, Oxford, UK
| |
Collapse
|
6
|
Rangaprakash D, Dretsch MN, Katz JS, Denney TS, Deshpande G. Dynamics of Segregation and Integration in Directional Brain Networks: Illustration in Soldiers With PTSD and Neurotrauma. Front Neurosci 2019; 13:803. [PMID: 31507353 PMCID: PMC6716456 DOI: 10.3389/fnins.2019.00803] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 07/17/2019] [Indexed: 01/08/2023] Open
Abstract
Brain functioning relies on various segregated/specialized neural regions functioning as an integrated-interconnected network (i.e., metastability). Various psychiatric and neurologic disorders are associated with aberrant functioning of these brain networks. In this study, we present a novel framework integrating the strength and temporal variability of metastability in brain networks. We demonstrate that this approach provides novel mechanistic insights which enables better imaging-based predictions. Using whole-brain resting-state fMRI and a graph-theoretic framework, we integrated strength and temporal-variability of complex-network properties derived from effective connectivity networks, obtained from 87 U.S. Army soldiers consisting of healthy combat controls (n = 28), posttraumatic stress disorder (PTSD; n = 17), and PTSD with comorbid mild-traumatic brain injury (mTBI; n = 42). We identified prefrontal dysregulation of key subcortical and visual regions in PTSD/mTBI, with all network properties exhibiting lower variability over time, indicative of poorer flexibility. Larger impairment in the prefrontal-subcortical pathway but not prefrontal-visual pathway differentiated comorbid PTSD/mTBI from the PTSD group. Network properties of the prefrontal-subcortical pathway also had significant association (R 2 = 0.56) with symptom severity and neurocognitive performance; and were also found to possess high predictive ability (81.4% accuracy in classifying the disorders, explaining 66-72% variance in symptoms), identified through machine learning. Our framework explained 13% more variance in behaviors compared to the conventional framework. These novel insights and better predictions were made possible by our novel framework using static and time-varying network properties in our three-group scenario, advancing the mechanistic understanding of PTSD and comorbid mTBI. Our contribution has wide-ranging applications for network-level characterization of healthy brains as well as mental disorders.
Collapse
Affiliation(s)
- D Rangaprakash
- Department of Electrical and Computer Engineering, AU MRI Research Center, Auburn University, Auburn, AL, United States.,Departments of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, United States
| | - Michael N Dretsch
- U.S. Army Aeromedical Research Laboratory, Fort Rucker, AL, United States.,U.S. Army Medical Research Directorate-West, Walter Reed Army Institute for Research, Joint Base Lewis-McChord, WA, United States.,Department of Psychology, Auburn University, Auburn, AL, United States
| | - Jeffrey S Katz
- Department of Electrical and Computer Engineering, AU MRI Research Center, Auburn University, Auburn, AL, United States.,Department of Psychology, Auburn University, Auburn, AL, United States.,Alabama Advanced Imaging Consortium, Auburn, AL, United States.,Center for Neuroscience, Auburn University, Auburn, AL, United States
| | - Thomas S Denney
- Department of Electrical and Computer Engineering, AU MRI Research Center, Auburn University, Auburn, AL, United States.,Department of Psychology, Auburn University, Auburn, AL, United States.,Alabama Advanced Imaging Consortium, Auburn, AL, United States.,Center for Neuroscience, Auburn University, Auburn, AL, United States
| | - Gopikrishna Deshpande
- Department of Electrical and Computer Engineering, AU MRI Research Center, Auburn University, Auburn, AL, United States.,Department of Psychology, Auburn University, Auburn, AL, United States.,Alabama Advanced Imaging Consortium, Auburn, AL, United States.,Center for Neuroscience, Auburn University, Auburn, AL, United States.,Center for Health Ecology and Equity Research, Auburn University, Auburn, AL, United States.,Department of Psychiatry, National Institute of Mental Health and Neurosciences, Bengaluru, India
| |
Collapse
|
7
|
Ennion L, Hijmans J. Improving vibration perception in a patient with type 2 diabetes and sensory peripheral neuropathy. SOUTH AFRICAN JOURNAL OF PHYSIOTHERAPY 2019; 75:602. [PMID: 31392290 PMCID: PMC6676981 DOI: 10.4102/sajp.v75i1.602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 05/31/2019] [Indexed: 11/29/2022] Open
Abstract
Introduction Diabetes mellitus (DM) and its related sensory peripheral neuropathy (SPN) are the biggest risk factors for foot ulcer formation and lower limb amputation. Reduced vibration perception results in less sensitivity to pressure and is a known risk factor for diabetic foot ulcers. Improving vibration perception in the feet of people with SPN could be protective against foot ulcers. The aim of this study was to determine if a therapeutic vibrating insole, used for 35 consecutive days, could improve vibration perception in a patient with type 2 DM. Patient presentation The patient was a 63 year-old male with a medical history of peripheral vascular disease, controlled hypertension, hyperlipidaemia, artherosclerosis and SPN secondary to controlled type 2 diabetes. Management and outcome The patient used the insoles for 20 min a day for 35 consecutive days. Vibration perception thresholds were measured four times in total: once at baseline, immediately post intervention, 1 month and 10 months later. Vibration perception threshold decreased with an average of 22 V (range 6 V–34 V) dependant on the tested location and time after intervention. The improvement remained after 1 and 10 months. Conclusion The use of a vibrating insole as a therapeutic device improved this patient’s perception of vibration in his feet. Clinically, vibrating insoles potentially might reduce the risk for ulcer formation and subsequent lower limb amputation in patients with DM and SPN. Clinical implications Using a vibrating insole therapeutically, can potentially improve the perception of vibration and pressure in patients with sensory peripheral neuropathy secondary to type 2 diabetes mellitus. Improved vibration perception might reduce the risk for diabetic ulcer formation and subsequent lower limb amputation.
Collapse
Affiliation(s)
- Liezel Ennion
- Department of Physiotherapy, University of the Western Cape, Cape Town, South Africa
| | - Juha Hijmans
- University of Groningen, University Medical Center Groningen, Department of Rehabilitation Medicine, Groningen, the Netherlands
| |
Collapse
|
8
|
McCormick M, Reyna VF, Ball K, Katz JS, Deshpande G. Neural Underpinnings of Financial Decision Bias in Older Adults: Putative Theoretical Models and a Way to Reconcile Them. Front Neurosci 2019; 13:184. [PMID: 30930732 PMCID: PMC6427068 DOI: 10.3389/fnins.2019.00184] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/15/2019] [Indexed: 12/31/2022] Open
Affiliation(s)
- Michael McCormick
- Department of Psychology, Auburn University, Auburn, AL, United States
| | - Valerie F. Reyna
- Human Neuroscience Institute, Cornell University, Ithaca, NY, United States
- Department of Human Development, Cornell University, Ithaca, NY, United States
- Center for Behavioral Economics and Decision Research, Cornell University, Ithaca, NY, United States
- Magnetic Resonance Imaging Facility, Cornell University, Ithaca, NY, United States
| | - Karlene Ball
- Center for Research on Applied Gerontology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jeffrey S. Katz
- Department of Psychology, Auburn University, Auburn, AL, United States
- Department of Electrical Computer Engineering, AU MRI Research Center, Auburn University, Auburn, AL, United States
- Center for Neuroscience, Auburn University, Auburn, AL, United States
- Alabama Advanced Imaging Consortium, Birmingham, AL, United States
| | - Gopikrishna Deshpande
- Department of Psychology, Auburn University, Auburn, AL, United States
- Department of Electrical Computer Engineering, AU MRI Research Center, Auburn University, Auburn, AL, United States
- Center for Neuroscience, Auburn University, Auburn, AL, United States
- Alabama Advanced Imaging Consortium, Birmingham, AL, United States
- Center for Health Ecology and Equity Research, Auburn University, Auburn, AL, United States
| |
Collapse
|
9
|
Bielczyk NZ, Uithol S, van Mourik T, Anderson P, Glennon JC, Buitelaar JK. Disentangling causal webs in the brain using functional magnetic resonance imaging: A review of current approaches. Netw Neurosci 2019; 3:237-273. [PMID: 30793082 PMCID: PMC6370462 DOI: 10.1162/netn_a_00062] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 06/08/2018] [Indexed: 01/05/2023] Open
Abstract
In the past two decades, functional Magnetic Resonance Imaging (fMRI) has been used to relate neuronal network activity to cognitive processing and behavior. Recently this approach has been augmented by algorithms that allow us to infer causal links between component populations of neuronal networks. Multiple inference procedures have been proposed to approach this research question but so far, each method has limitations when it comes to establishing whole-brain connectivity patterns. In this paper, we discuss eight ways to infer causality in fMRI research: Bayesian Nets, Dynamical Causal Modelling, Granger Causality, Likelihood Ratios, Linear Non-Gaussian Acyclic Models, Patel's Tau, Structural Equation Modelling, and Transfer Entropy. We finish with formulating some recommendations for the future directions in this area.
Collapse
Affiliation(s)
- Natalia Z. Bielczyk
- Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
- Department of Cognitive Neuroscience, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Sebo Uithol
- Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
- Bernstein Centre for Computational Neuroscience, Charité Universitätsmedizin, Berlin, Germany
| | - Tim van Mourik
- Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
- Department of Cognitive Neuroscience, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Paul Anderson
- Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
- Faculty of Science, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Jeffrey C. Glennon
- Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
- Department of Cognitive Neuroscience, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Jan K. Buitelaar
- Donders Institute for Brain, Cognition and Behavior, Nijmegen, the Netherlands
- Department of Cognitive Neuroscience, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| |
Collapse
|
10
|
Rao NP, Deshpande G, Gangadhar KB, Arasappa R, Varambally S, Venkatasubramanian G, Ganagadhar BN. Directional brain networks underlying OM chanting. Asian J Psychiatr 2018; 37:20-25. [PMID: 30099280 DOI: 10.1016/j.ajp.2018.08.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Revised: 08/01/2018] [Accepted: 08/01/2018] [Indexed: 02/05/2023]
Abstract
OM chanting is an ancient technique of Indian meditation. OM chanting is associated with an experience of relaxation, changes in autonomic balance and deactivation of limbic brain regions. While functional localization is important, how brain regions interact with each other has been shown to underlie various brain functions. Therefore, in this study, we tested the hypothesis that there is reduced communication between deactivated regions during OM chanting. In order to do so, we employed multivariate autoregressive model (MVAR) based Granger causality to obtain directional connectivity between deactivated regions. fMRI scans of 12 right handed healthy volunteers (9 Men) from a previously published study was used in which participants performed OM chanting and a control condition in a block design. We found that outputs from insula, anterior cingulate and orbitofrontal cortices were significantly reduced in OM condition. Of interest is the reduction of outputs from these regions to limbic area amygdala. Modulation of brain regions involved in emotion processing and implicated in major depressive disorder (MDD) raises a potential possibility of OM chanting in the treatment of MDD.
Collapse
Affiliation(s)
- Naren P Rao
- National Institute of Mental Health and Neurosciences, Bangalore, India.
| | - Gopikrishna Deshpande
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, USA; Department of Psychology, Auburn University, Auburn, AL, USA; Alabama Advanced Imaging Consortium, Auburn University and University of Alabama Birmingham, AL, USA
| | | | - Rashmi Arasappa
- National Institute of Mental Health and Neurosciences, Bangalore, India
| | | | | | | |
Collapse
|
11
|
Zhao X, Rangaprakash D, Yuan B, Denney TS, Katz JS, Dretsch MN, Deshpande G. Investigating the Correspondence of Clinical Diagnostic Grouping With Underlying Neurobiological and Phenotypic Clusters Using Unsupervised Machine Learning. FRONTIERS IN APPLIED MATHEMATICS AND STATISTICS 2018; 4:25. [PMID: 30393630 PMCID: PMC6214192 DOI: 10.3389/fams.2018.00025] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Many brain-based disorders are traditionally diagnosed based on clinical interviews and behavioral assessments, which are recognized to be largely imperfect. Therefore, it is necessary to establish neuroimaging-based biomarkers to improve diagnostic precision. Resting-state functional magnetic resonance imaging (rs-fMRI) is a promising technique for the characterization and classification of varying disorders. However, most of these classification methods are supervised, i.e., they require a priori clinical labels to guide classification. In this study, we adopted various unsupervised clustering methods using static and dynamic rs-fMRI connectivity measures to investigate whether the clinical diagnostic grouping of different disorders is grounded in underlying neurobiological and phenotypic clusters. In order to do so, we derived a general analysis pipeline for identifying different brain-based disorders using genetic algorithm-based feature selection, and unsupervised clustering methods on four different datasets; three of them-ADNI, ADHD-200, and ABIDE-which are publicly available, and a fourth one-PTSD and PCS-which was acquired in-house. Using these datasets, the effectiveness of the proposed pipeline was verified on different disorders: Attention Deficit Hyperactivity Disorder (ADHD), Alzheimer's Disease (AD), Autism Spectrum Disorder (ASD), Post-Traumatic Stress Disorder (PTSD), and Post-Concussion Syndrome (PCS). For ADHD and AD, highest similarity was achieved between connectivity and phenotypic clusters, whereas for ASD and PTSD/PCS, highest similarity was achieved between connectivity and clinical diagnostic clusters. For multi-site data (ABIDE and ADHD-200), we report site-specific results. We also reported the effect of elimination of outlier subjects for all four datasets. Overall, our results suggest that neurobiological and phenotypic biomarkers could potentially be used as an aid by the clinician, in additional to currently available clinical diagnostic standards, to improve diagnostic precision. Data and source code used in this work is publicly available at https://github.com/xinyuzhao/identification-of-brain-based-disorders.git.
Collapse
Affiliation(s)
- Xinyu Zhao
- Department of Electrical and Computer Engineering, AU MRI Research Center, Auburn University, Auburn, AL, United States
- Quora, Inc., Mountain View, CA, United States
| | - D. Rangaprakash
- Department of Electrical and Computer Engineering, AU MRI Research Center, Auburn University, Auburn, AL, United States
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, United States
| | - Bowen Yuan
- Department of Electrical and Computer Engineering, AU MRI Research Center, Auburn University, Auburn, AL, United States
| | - Thomas S. Denney
- Department of Electrical and Computer Engineering, AU MRI Research Center, Auburn University, Auburn, AL, United States
- Department of Psychology, Auburn University, Auburn, AL, United States
- Alabama Advanced Imaging Consortium, Auburn University, University of Alabama at Birmingham, Birmingham, AL, United States
- Center for Neuroscience, Auburn University, Auburn, AL, United States
| | - Jeffrey S. Katz
- Department of Electrical and Computer Engineering, AU MRI Research Center, Auburn University, Auburn, AL, United States
- Department of Psychology, Auburn University, Auburn, AL, United States
- Alabama Advanced Imaging Consortium, Auburn University, University of Alabama at Birmingham, Birmingham, AL, United States
- Center for Neuroscience, Auburn University, Auburn, AL, United States
| | - Michael N. Dretsch
- Human Dimension Division, HQ TRADOC, Fort Eustis, VA, United States
- U.S. Army Aeromedical Research Laboratory, Fort Rucker, AL, United States
| | - Gopikrishna Deshpande
- Department of Electrical and Computer Engineering, AU MRI Research Center, Auburn University, Auburn, AL, United States
- Department of Psychology, Auburn University, Auburn, AL, United States
- Alabama Advanced Imaging Consortium, Auburn University, University of Alabama at Birmingham, Birmingham, AL, United States
- Center for Neuroscience, Auburn University, Auburn, AL, United States
- Center for Health Ecology and Equity Research, Auburn University, Auburn, AL, United States
| |
Collapse
|
12
|
Ramaihgari B, Pustovyy OM, Waggoner P, Beyers RJ, Wildey C, Morrison E, Salibi N, Katz JS, Denney TS, Vodyanoy VJ, Deshpande G. Zinc Nanoparticles Enhance Brain Connectivity in the Canine Olfactory Network: Evidence From an fMRI Study in Unrestrained Awake Dogs. Front Vet Sci 2018; 5:127. [PMID: 30013977 PMCID: PMC6036133 DOI: 10.3389/fvets.2018.00127] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 05/23/2018] [Indexed: 01/01/2023] Open
Abstract
Prior functional Magnetic Resonance Imaging (fMRI) studies have indicated increased neural activation when zinc nanoparticles are added to odorants in canines. Here we demonstrate that zinc nanoparticles up-regulate directional brain connectivity in parts of the canine olfactory network. This provides an explanation for previously reported enhancement in the odor detection capability of the dogs in the presence of zinc nanoparticles. In this study, we obtained fMRI data from awake and unrestrained dogs while they were being exposed to odorants with and without zinc nanoparticles, zinc nanoparticles suspended in water vapor, as well as just water vapor alone. We obtained directional connectivity between the brain regions of the olfactory network that were significantly stronger for the condition of odorant + zinc nanoparticles compared to just odorants, water vapor + zinc nanoparticles and water vapor alone. We observed significant strengthening of the paths of the canine olfactory network in the presence of zinc nanoparticles. This result indicates that zinc nanoparticles could potentially be used to increase canine detection capabilities in the environments of very low concentrations of the odorants, which would have otherwise been undetected.
Collapse
Affiliation(s)
- Bhavitha Ramaihgari
- Auburn University MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, United States
| | - Oleg M. Pustovyy
- Department of Anatomy, Physiology and Pharmacology, Auburn University, Auburn, AL, United States
| | - Paul Waggoner
- Canine Detection Research Institute, Auburn UniversityAuburn, AL, United States
| | - Ronald J. Beyers
- Auburn University MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, United States
| | - Chester Wildey
- MRRA Inc., University of Alabama at Birmingham, Euless, TX, United States
| | - Edward Morrison
- Department of Anatomy, Physiology and Pharmacology, Auburn University, Auburn, AL, United States
| | - Nouha Salibi
- Auburn University MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, United States
- MR Research and Development, Siemens Healthcare, Malvern, PA, United States
| | - Jeffrey S. Katz
- Auburn University MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, United States
- Department of Psychology, Auburn University, Auburn, AL, United States
- Alabama Advanced Imaging Consortium, Auburn University and University of Alabama Birmingham, Birmingham, AL, United States
| | - Thomas S. Denney
- Auburn University MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, United States
- Department of Psychology, Auburn University, Auburn, AL, United States
- Alabama Advanced Imaging Consortium, Auburn University and University of Alabama Birmingham, Birmingham, AL, United States
| | - Vitaly J. Vodyanoy
- Department of Anatomy, Physiology and Pharmacology, Auburn University, Auburn, AL, United States
| | - Gopikrishna Deshpande
- Auburn University MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, United States
- Department of Psychology, Auburn University, Auburn, AL, United States
- Alabama Advanced Imaging Consortium, Auburn University and University of Alabama Birmingham, Birmingham, AL, United States
- Center for Health Ecology and Equity Research, Auburn University, Auburn, AL, United States
| |
Collapse
|
13
|
Singh AK, Phillips F, Merabet LB, Sinha P. Why Does the Cortex Reorganize after Sensory Loss? Trends Cogn Sci 2018; 22:569-582. [PMID: 29907530 DOI: 10.1016/j.tics.2018.04.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 04/01/2018] [Accepted: 04/17/2018] [Indexed: 01/05/2023]
Abstract
A growing body of evidence demonstrates that the brain can reorganize dramatically following sensory loss. Although the existence of such neuroplastic crossmodal changes is not in doubt, the functional significance of these changes remains unclear. The dominant belief is that reorganization is compensatory. However, results thus far do not unequivocally indicate that sensory deprivation results in markedly enhanced abilities in other senses. Here, we consider alternative reasons besides sensory compensation that might drive the brain to reorganize after sensory loss. One such possibility is that the cortex reorganizes not to confer functional benefits, but to avoid undesirable physiological consequences of sensory deafferentation. Empirical assessment of the validity of this and other possibilities defines a rich program for future research.
Collapse
Affiliation(s)
- Amy Kalia Singh
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Flip Phillips
- Department of Psychology and Neuroscience, Skidmore College, Saratoga Springs, NY, USA
| | - Lotfi B Merabet
- Laboratory for Visual Neuroplasticity, Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Pawan Sinha
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
| |
Collapse
|
14
|
Hirtz R, Weiss T, Huonker R, Witte OW. Impact of transcranial direct current stimulation on structural plasticity of the somatosensory system. J Neurosci Res 2018; 96:1367-1379. [PMID: 29876962 DOI: 10.1002/jnr.24258] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 04/22/2018] [Accepted: 04/23/2018] [Indexed: 01/21/2023]
Abstract
While there is a growing body of evidence regarding the behavioral and neurofunctional changes in response to the longitudinal delivery of transcranial direct current stimulation (tDCS), there is limited evidence regarding its structural effects. Therefore, the present study was intended to investigate the effect of repeatedly applied anodal tDCS over the primary somatosensory cortex on the gray matter (GM) and white matter (WM) compartment of the brain. Structural tDCS effects were, moreover, related to effects evidenced by functional imaging and behavioral assessment. tDCS was applied over the course of 5 days in 25 subjects with concomitant assessment of tactile acuity of the right and left index finger as well as imaging at baseline, after the last delivery of tDCS and at follow-up 4 weeks thereafter. Irrespective of the stimulation condition (anodal vs. sham), voxel-based morphometry revealed a behaviorally relevant decrease of GM in the precuneus co-localized with a functional change of its activity. Moreover, there was a decrease in GM of the bilateral lingual gyrus and the right cerebellum. Diffusion tensor imaging analysis showed an increase of fractional anisotropy exclusively in the tDCSanodal condition in the left frontal cortex affecting the final stretch of a somatosensory decision making network comprising the middle and superior frontal gyrus as well as regions adjacent to the genu of the corpus callosum. Thus, this is the first study in humans to identify structural plasticity in the GM compartment and tDCS-specific changes in the WM compartment in response to somatosensory learning.
Collapse
Affiliation(s)
- Raphael Hirtz
- Hans Berger Department of Neurology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
- Pediatric Endocrinology and Diabetology, Essen University Hospital, Essen, Germany
| | - Thomas Weiss
- Department of Biological and Clinical Psychology, Friedrich Schiller University, Jena, Germany
| | - Ralph Huonker
- Brain Imaging Center, Hans Berger Department of Neurology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Otto W Witte
- Hans Berger Department of Neurology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| |
Collapse
|
15
|
Impact of transcranial direct current stimulation on somatosensory transfer learning: When the secondary somatosensory cortex comes into play. Brain Res 2018; 1689:98-108. [DOI: 10.1016/j.brainres.2018.03.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 03/11/2018] [Accepted: 03/26/2018] [Indexed: 11/22/2022]
|
16
|
Rangaprakash D, Bohon C, Lawrence KE, Moody T, Morfini F, Khalsa SS, Strober M, Feusner JD. Aberrant Dynamic Connectivity for Fear Processing in Anorexia Nervosa and Body Dysmorphic Disorder. Front Psychiatry 2018; 9:273. [PMID: 29997532 PMCID: PMC6028703 DOI: 10.3389/fpsyt.2018.00273] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 06/05/2018] [Indexed: 01/20/2023] Open
Abstract
Anorexia nervosa (AN) and body dysmorphic disorder (BDD) share distorted perceptions of appearance with extreme negative emotion, yet the neural phenotypes of emotion processing remain underexplored in them, and they have never been directly compared. We sought to determine if shared and disorder-specific fronto-limbic connectivity patterns characterize these disorders. FMRI data was obtained from three unmedicated groups: BDD (n = 32), weight-restored AN (n = 25), and healthy controls (HC; n = 37), while they viewed fearful faces and rated their own degree of fearfulness in response. We performed dynamic effective connectivity modeling with medial prefrontal cortex (mPFC), rostral anterior cingulate cortex (rACC), and amygdala as regions-of-interest (ROI), and assessed associations between connectivity and clinical variables. HCs exhibited significant within-group bidirectional mPFC-amygdala connectivity, which increased across the blocks, whereas BDD participants exhibited only significant mPFC-to-amygdala connectivity (P < 0.05, family-wise error corrected). In contrast, participants with AN lacked significant prefrontal-amygdala connectivity in either direction. AN showed significantly weaker mPFC-to-amygdala connectivity compared to HCs (P = 0.0015) and BDD (P = 0.0050). The mPFC-to-amygdala connectivity was associated with greater subjective fear ratings (R2 = 0.11, P = 0.0016), eating disorder symptoms (R2 = 0.33, P = 0.0029), and anxiety (R2 = 0.29, P = 0.0055) intensity scores. Our findings, which suggest a complex nosological relationship, have implications for understanding emotion regulation circuitry in these related psychiatric disorders, and may have relevance for current and novel therapeutic approaches.
Collapse
Affiliation(s)
- D Rangaprakash
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, United States
| | - Cara Bohon
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, United States
| | - Katherine E Lawrence
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, United States
| | - Teena Moody
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, United States
| | - Francesca Morfini
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, United States
| | - Sahib S Khalsa
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, United States.,Oxley College of Health Sciences, University of Tulsa, Tulsa, OK, United States.,Laureate Institute for Brain Research, University of Tulsa, Tulsa, OK, United States
| | - Michael Strober
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, United States
| | - Jamie D Feusner
- Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, CA, United States
| |
Collapse
|
17
|
Regionally Specific Regulation of Sensorimotor Network Connectivity Following Tactile Improvement. Neural Plast 2017; 2017:5270532. [PMID: 29230329 PMCID: PMC5688375 DOI: 10.1155/2017/5270532] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/28/2017] [Indexed: 01/15/2023] Open
Abstract
Correlations between inherent, task-free low-frequency fluctuations in the blood oxygenation level-dependent (BOLD) signals of the brain provide a potent tool to delineate its functional architecture in terms of intrinsic functional connectivity (iFC). Still, it remains unclear how iFC is modulated during learning. We employed whole-brain resting-state magnetic resonance imaging prior to and after training-independent repetitive sensory stimulation (rSS), which is known to induce somatosensory cortical reorganization. We investigated which areas in the sensorimotor network are susceptible to neural plasticity (i.e., where changes in functional connectivity occurred) and where iFC might be indicative of enhanced tactile performance. We hypothesized iFC to increase in those brain regions primarily receiving the afferent tactile input. Strengthened intrinsic connectivity within the sensorimotor network after rSS was found not only in the postcentral gyrus contralateral to the stimulated hand, but also in associative brain regions, where iFC correlated positively with tactile performance or learning. We also observed that rSS led to attenuation of the network at higher cortical levels, which possibly promotes facilitation of tactile discrimination. We found that resting-state BOLD fluctuations are linked to behavioral performance and sensory learning, indicating that network fluctuations at rest are predictive of behavioral changes and neuroplasticity.
Collapse
|
18
|
Rangaprakash D, Dretsch MN, Venkataraman A, Katz JS, Denney TS, Deshpande G. Identifying disease foci from static and dynamic effective connectivity networks: Illustration in soldiers with trauma. Hum Brain Mapp 2017; 39:264-287. [PMID: 29058357 DOI: 10.1002/hbm.23841] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 08/29/2017] [Accepted: 10/01/2017] [Indexed: 12/15/2022] Open
Abstract
Brain connectivity studies report group differences in pairwise connection strengths. While informative, such results are difficult to interpret since our understanding of the brain relies on region-based properties, rather than on connection information. Given that large disruptions in the brain are often caused by a few pivotal sources, we propose a novel framework to identify the sources of functional disruption from effective connectivity networks. Our approach integrates static and time-varying effective connectivity modeling in a probabilistic framework, to identify aberrant foci and the corresponding aberrant connectomics network. Using resting-state fMRI, we illustrate the utility of this novel approach in U.S. Army soldiers (N = 87) with posttraumatic stress disorder (PTSD), mild traumatic brain injury (mTBI) and combat controls. Additionally, we employed machine-learning classification to identify those significant connectivity features that possessed high predictive ability. We identified three disrupted foci (middle frontal gyrus [MFG], insula, hippocampus), and an aberrant prefrontal-subcortical-parietal network of information flow. We found the MFG to be the pivotal focus of network disruption, with aberrant strength and temporal-variability of effective connectivity to the insula, amygdala and hippocampus. These connectivities also possessed high predictive ability (giving a classification accuracy of 81%); and they exhibited significant associations with symptom severity and neurocognitive functioning. In summary, dysregulation originating in the MFG caused elevated and temporally less-variable connectivity in subcortical regions, followed by a similar effect on parietal memory-related regions. This mechanism likely contributes to the reduced control over traumatic memories leading to re-experiencing, hyperarousal and flashbacks observed in soldiers with PTSD and mTBI. Hum Brain Mapp 39:264-287, 2018. © 2017 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- D Rangaprakash
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, USA.,Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, CA, USA
| | - Michael N Dretsch
- U.S. Army Aeromedical Research Laboratory, Fort Rucker, Alabama.,Human Dimension Division, HQ TRADOC, Fort Eustis, Virgina
| | - Archana Venkataraman
- Department of Electrical and Computer Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Jeffrey S Katz
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, USA.,Department of Psychology, Auburn University, Auburn, Alabama.,Alabama Advanced Imaging Consortium, USA
| | - Thomas S Denney
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, USA.,Department of Psychology, Auburn University, Auburn, Alabama.,Alabama Advanced Imaging Consortium, USA
| | - Gopikrishna Deshpande
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, USA.,Department of Psychology, Auburn University, Auburn, Alabama.,Alabama Advanced Imaging Consortium, USA
| |
Collapse
|
19
|
Bielczyk NZ, Llera A, Buitelaar JK, Glennon JC, Beckmann CF. The impact of hemodynamic variability and signal mixing on the identifiability of effective connectivity structures in BOLD fMRI. Brain Behav 2017; 7:e00777. [PMID: 28828228 PMCID: PMC5561328 DOI: 10.1002/brb3.777] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Accepted: 06/07/2017] [Indexed: 01/03/2023] Open
Abstract
PURPOSE Multiple computational studies have demonstrated that essentially all current analytical approaches to determine effective connectivity perform poorly when applied to synthetic functional Magnetic Resonance Imaging (fMRI) datasets. In this study, we take a theoretical approach to investigate the potential factors facilitating and hindering effective connectivity research in fMRI. MATERIALS AND METHODS In this work, we perform a simulation study with use of Dynamic Causal Modeling generative model in order to gain new insights on the influence of factors such as the slow hemodynamic response, mixed signals in the network and short time series, on the effective connectivity estimation in fMRI studies. RESULTS First, we perform a Linear Discriminant Analysis study and find that not the hemodynamics itself but mixed signals in the neuronal networks are detrimental to the signatures of distinct connectivity patterns. This result suggests that for statistical methods (which do not involve lagged signals), deconvolving the BOLD responses is not necessary, but at the same time, functional parcellation into Regions of Interest (ROIs) is essential. Second, we study the impact of hemodynamic variability on the inference with use of lagged methods. We find that the local hemodynamic variability provide with an upper bound on the success rate of the lagged methods. Furthermore, we demonstrate that upsampling the data to TRs lower than the TRs in state-of-the-art datasets does not influence the performance of the lagged methods. CONCLUSIONS Factors such as background scale-free noise and hemodynamic variability have a major impact on the performance of methods for effective connectivity research in functional Magnetic Resonance Imaging.
Collapse
Affiliation(s)
- Natalia Z. Bielczyk
- Donders Institute for Brain, Cognition and BehaviorNijmegenThe Netherlands
- Radboud University Nijmegen Medical CentreNijmegenThe Netherlands
| | - Alberto Llera
- Oxford Centre for Functional MRI of the BrainJohn Radcliffe HospitalOxfordUK
| | - Jan K. Buitelaar
- Donders Institute for Brain, Cognition and BehaviorNijmegenThe Netherlands
- Radboud University Nijmegen Medical CentreNijmegenThe Netherlands
| | - Jeffrey C. Glennon
- Donders Institute for Brain, Cognition and BehaviorNijmegenThe Netherlands
- Radboud University Nijmegen Medical CentreNijmegenThe Netherlands
| | - Christian F. Beckmann
- Donders Institute for Brain, Cognition and BehaviorNijmegenThe Netherlands
- Radboud University Nijmegen Medical CentreNijmegenThe Netherlands
- Oxford Centre for Functional MRI of the BrainJohn Radcliffe HospitalOxfordUK
| |
Collapse
|
20
|
Zhao S, Rangaprakash D, Venkataraman A, Liang P, Deshpande G. Investigating Focal Connectivity Deficits in Alzheimer's Disease Using Directional Brain Networks Derived from Resting-State fMRI. Front Aging Neurosci 2017; 9:211. [PMID: 28729831 PMCID: PMC5498531 DOI: 10.3389/fnagi.2017.00211] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 06/15/2017] [Indexed: 01/17/2023] Open
Abstract
Connectivity analysis of resting-state fMRI has been widely used to identify biomarkers of Alzheimer's disease (AD) based on brain network aberrations. However, it is not straightforward to interpret such connectivity results since our understanding of brain functioning relies on regional properties (activations and morphometric changes) more than connections. Further, from an interventional standpoint, it is easier to modulate the activity of regions (using brain stimulation, neurofeedback, etc.) rather than connections. Therefore, we employed a novel approach for identifying focal directed connectivity deficits in AD compared to healthy controls. In brief, we present a model of directed connectivity (using Granger causality) that characterizes the coupling among different regions in healthy controls and Alzheimer's disease. We then characterized group differences using a (between-subject) generative model of pathology, which generates latent connectivity variables that best explain the (within-subject) directed connectivity. Crucially, our generative model at the second (between-subject) level explains connectivity in terms of local or regionally specific abnormalities. This allows one to explain disconnections among multiple regions in terms of regionally specific pathology; thereby offering a target for therapeutic intervention. Two foci were identified, locus coeruleus in the brain stem and right orbitofrontal cortex. Corresponding disrupted connectivity network associated with the foci showed that the brainstem is the critical focus of disruption in AD. We further partitioned the aberrant connectomic network into four unique sub-networks, which likely leads to symptoms commonly observed in AD. Our findings suggest that fMRI studies of AD, which have been largely cortico-centric, could in future investigate the role of brain stem in AD.
Collapse
Affiliation(s)
- Sinan Zhao
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn UniversityAuburn, AL, United States
| | - D Rangaprakash
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn UniversityAuburn, AL, United States.,Department of Psychiatry and Biobehavioral Sciences, University of California, Los AngelesLos Angeles, CA, United States
| | - Archana Venkataraman
- Department of Electrical and Computer Engineering, Johns Hopkins UniversityBaltimore, MD, United States
| | - Peipeng Liang
- Department of Radiology, Xuanwu Hospital, Capital Medical UniversityBeijing, China.,Beijing Key Laboratory of Magnetic Resonance Imaging and Brain InformaticsBeijing, China.,Key Laboratory for Neurodegenerative Diseases, Ministry of EducationBeijing, China
| | - Gopikrishna Deshpande
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn UniversityAuburn, AL, United States.,Department of Psychology, Auburn UniversityAuburn, AL, United States.,Alabama Advanced Imaging Consortium, Auburn University and University of Alabama BirminghamAuburn, AL, United States
| |
Collapse
|
21
|
Jin C, Jia H, Lanka P, Rangaprakash D, Li L, Liu T, Hu X, Deshpande G. Dynamic brain connectivity is a better predictor of PTSD than static connectivity. Hum Brain Mapp 2017; 38:4479-4496. [PMID: 28603919 DOI: 10.1002/hbm.23676] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 05/23/2017] [Indexed: 12/24/2022] Open
Abstract
Using resting-state functional magnetic resonance imaging, we test the hypothesis that subjects with post-traumatic stress disorder (PTSD) are characterized by reduced temporal variability of brain connectivity compared to matched healthy controls. Specifically, we test whether PTSD is characterized by elevated static connectivity, coupled with decreased temporal variability of those connections, with the latter providing greater sensitivity toward the pathology than the former. Static functional connectivity (FC; nondirectional zero-lag correlation) and static effective connectivity (EC; directional time-lagged relationships) were obtained over the entire brain using conventional models. Dynamic FC and dynamic EC were estimated by letting the conventional models to vary as a function of time. Statistical separation and discriminability of these metrics between the groups and their ability to accurately predict the diagnostic label of a novel subject were ascertained using separate support vector machine classifiers. Our findings support our hypothesis that PTSD subjects have stronger static connectivity, but reduced temporal variability of connectivity. Further, machine learning classification accuracy obtained with dynamic FC and dynamic EC was significantly higher than that obtained with static FC and static EC, respectively. Furthermore, results also indicate that the ease with which brain regions engage or disengage with other regions may be more sensitive to underlying pathology than the strength with which they are engaged. Future studies must examine whether this is true only in the case of PTSD or is a general organizing principle in the human brain. Hum Brain Mapp 38:4479-4496, 2017. © 2017 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Changfeng Jin
- The Mental Health Institute, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Hao Jia
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama.,Department of Automation, College of Information Engineering, Taiyuan University of Technology, Taiyuan, Shanxi, China
| | - Pradyumna Lanka
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama
| | - D Rangaprakash
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama.,Department of Psychiatry and Biobehavioral Sciences, University of California Los Angeles, Los Angeles, California
| | - Lingjiang Li
- The Mental Health Institute, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Tianming Liu
- Cortical Architecture Imaging and Discovery Lab, Department of Computer Science and Bioimaging Research Center, University of Georgia, Athens, Georgia
| | - Xiaoping Hu
- Center for Advanced Neuroimaging, Department of Bioengineering, University of California, Riverside, California
| | - Gopikrishna Deshpande
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, Alabama.,Department of Psychology, Auburn University, Auburn, Alabama.,Alabama Advanced Imaging Consortium, Auburn University and University of Alabama Birmingham, Alabama
| |
Collapse
|
22
|
Sreenivasan K, Zhuang X, Banks SJ, Mishra V, Yang Z, Deshpande G, Cordes D. Olfactory Network Differences in Master Sommeliers: Connectivity Analysis Using Granger Causality and Graph Theoretical Approach. Brain Connect 2017; 7:123-136. [PMID: 28125912 DOI: 10.1089/brain.2016.0458] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Previous studies investigating the differences in olfactory processing and judgments between trained sommeliers and controls have shown increased activations in brain regions involving higher level cognitive processes in sommeliers. However, there is little information about the influence of expertise on causal connectivity and topological properties of the connectivity networks between these regions. Therefore, the current study focuses on addressing these questions in a functional magnetic resonance imaging (fMRI) study of olfactory perception in Master Sommeliers. fMRI data were acquired from Master Sommeliers and control participants during different olfactory and nonolfactory tasks. Mean time series were extracted from 90 different regions of interest (ROIs; based on Automated Anatomical Labeling atlas). The underlying neuronal variables were extracted using blind hemodynamic deconvolution and then input into a dynamic multivariate autoregressive model to obtain connectivity between every pair of ROIs as a function of time. These connectivity values were then statistically compared to obtain paths that were significantly different between the two groups. The obtained connectivity matrices were further studied using graph theoretical methods. In sommeliers, significantly greater connectivity was observed in connections involving the precuneus, caudate, putamen, and several frontal and temporal regions. The controls showed increased connectivity from the left hippocampus to the frontal regions. Furthermore, the sommeliers exhibited significantly higher small-world topology than the controls. These findings are significant, given that learning about neuroplasticity in adulthood in these regions may then have added clinical importance in diseases such as Alzheimer's and Parkinson's where early neurodegeneration is isolated to regions important in smell.
Collapse
Affiliation(s)
| | - Xiaowei Zhuang
- 1 Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, Nevada
| | - Sarah J Banks
- 1 Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, Nevada
| | - Virendra Mishra
- 1 Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, Nevada
| | - Zhengshi Yang
- 1 Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, Nevada
| | - Gopikrishna Deshpande
- 2 Department of Electrical and Computer Engineering, AU MRI Research Center, Auburn University , Auburn, Alabama
- 3 Department of Psychology, Auburn University , Auburn, Alabama
- 4 Alabama Advanced Imaging Consortium, Auburn University and University of Alabama Birmingham , Birmingham, Alabama
| | - Dietmar Cordes
- 1 Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, Nevada
- 5 Department of Psychology and Neuroscience, University of Colorado, Boulder, Colorado
| |
Collapse
|
23
|
Lacey S, Stilla R, Deshpande G, Zhao S, Stephens C, McCormick K, Kemmerer D, Sathian K. Engagement of the left extrastriate body area during body-part metaphor comprehension. BRAIN AND LANGUAGE 2017; 166:1-18. [PMID: 27951437 DOI: 10.1016/j.bandl.2016.11.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 09/13/2016] [Accepted: 11/17/2016] [Indexed: 06/06/2023]
Abstract
Grounded cognition explanations of metaphor comprehension predict activation of sensorimotor cortices relevant to the metaphor's source domain. We tested this prediction for body-part metaphors using functional magnetic resonance imaging while participants heard sentences containing metaphorical or literal references to body parts, and comparable control sentences. Localizer scans identified body-part-specific motor, somatosensory and visual cortical regions. Both subject- and item-wise analyses showed that, relative to control sentences, metaphorical but not literal sentences evoked limb metaphor-specific activity in the left extrastriate body area (EBA), paralleling the EBA's known visual limb-selectivity. The EBA focus exhibited resting-state functional connectivity with ipsilateral semantic processing regions. In some of these regions, the strength of resting-state connectivity correlated with individual preference for verbal processing. Effective connectivity analyses showed that, during metaphor comprehension, activity in some semantic regions drove that in the EBA. These results provide converging evidence for grounding of metaphor processing in domain-specific sensorimotor cortical activity.
Collapse
Affiliation(s)
- Simon Lacey
- Department of Neurology, Emory University, Atlanta, GA, USA
| | - Randall Stilla
- Department of Neurology, Emory University, Atlanta, GA, USA
| | - Gopikrishna Deshpande
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, USA; Department of Psychology, Auburn University, Auburn, AL, USA; Alabama Advanced Imaging Consortium, Auburn University & University of Alabama, Birmingham, AL, USA
| | - Sinan Zhao
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, USA
| | | | - Kelly McCormick
- Department of Psychology, Emory University, Atlanta, GA, USA
| | - David Kemmerer
- Department of Psychological Sciences, Purdue University, West Lafayette, IN, USA; Department of Speech, Language, and Hearing Sciences, Purdue University, West Lafayette, IN, USA
| | - K Sathian
- Department of Neurology, Emory University, Atlanta, GA, USA; Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA; Department of Psychology, Emory University, Atlanta, GA, USA; Rehabilitation R&D Center for Visual and Neurocognitive Rehabilitation, Atlanta VAMC, Decatur, GA, USA.
| |
Collapse
|
24
|
Predicting favorable and unfavorable consequences of perceptual learning: worsening and the peak shift. Exp Brain Res 2017; 235:1233-1245. [DOI: 10.1007/s00221-016-4866-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 12/23/2016] [Indexed: 10/20/2022]
|
25
|
Goodyear K, Parasuraman R, Chernyak S, Madhavan P, Deshpande G, Krueger F. Advice Taking from Humans and Machines: An fMRI and Effective Connectivity Study. Front Hum Neurosci 2016; 10:542. [PMID: 27867351 PMCID: PMC5095979 DOI: 10.3389/fnhum.2016.00542] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 10/12/2016] [Indexed: 11/23/2022] Open
Abstract
With new technological advances, advice can come from different sources such as machines or humans, but how individuals respond to such advice and the neural correlates involved need to be better understood. We combined functional MRI and multivariate Granger causality analysis with an X-ray luggage-screening task to investigate the neural basis and corresponding effective connectivity involved with advice utilization from agents framed as experts. Participants were asked to accept or reject good or bad advice from a human or machine agent with low reliability (high false alarm rate). We showed that unreliable advice decreased performance overall and participants interacting with the human agent had a greater depreciation of advice utilization during bad advice compared to the machine agent. These differences in advice utilization can be perceivably due to reevaluation of expectations arising from association of dispositional credibility for each agent. We demonstrated that differences in advice utilization engaged brain regions that may be associated with evaluation of personal characteristics and traits (precuneus, posterior cingulate cortex, temporoparietal junction) and interoception (posterior insula). We found that the right posterior insula and left precuneus were the drivers of the advice utilization network that were reciprocally connected to each other and also projected to all other regions. Our behavioral and neuroimaging results have significant implications for society because of progressions in technology and increased interactions with machines.
Collapse
Affiliation(s)
- Kimberly Goodyear
- Center for Alcohol and Addiction Studies, Department of Behavioral and Social Sciences, Brown University, ProvidenceRI, USA; Section on Clinical Psychoneuroendocrinology and Neuropsychopharmacology, National Institute on Alcohol Abuse and Alcoholism and National Institute on Drug Abuse, BethesdaMD, USA
| | - Raja Parasuraman
- Department of Psychology, George Mason University, Fairfax VA, USA
| | - Sergey Chernyak
- Molecular Neuroscience Department, George Mason University, Fairfax VA, USA
| | | | - Gopikrishna Deshpande
- Auburn University MRI Research Center, Department of Electrical & Computer Engineering, Auburn University, AuburnAL, USA; Department of Psychology, Auburn University, AuburnAL, USA; Alabama Advanced Imaging Consortium, Auburn University and University of Alabama, BirminghamAL, USA
| | - Frank Krueger
- Department of Psychology, George Mason University, FairfaxVA, USA; Molecular Neuroscience Department, George Mason University, FairfaxVA, USA
| |
Collapse
|
26
|
Debowska W, Wolak T, Nowicka A, Kozak A, Szwed M, Kossut M. Functional and Structural Neuroplasticity Induced by Short-Term Tactile Training Based on Braille Reading. Front Neurosci 2016; 10:460. [PMID: 27790087 PMCID: PMC5061995 DOI: 10.3389/fnins.2016.00460] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 09/26/2016] [Indexed: 11/30/2022] Open
Abstract
Neuroplastic changes induced by sensory learning have been recognized within the cortices of specific modalities as well as within higher ordered multimodal areas. The interplay between these areas is not fully understood, particularly in the case of somatosensory learning. Here we examined functional and structural changes induced by short-term tactile training based of Braille reading, a task that requires both significant tactile expertise and mapping of tactile input onto multimodal representations. Subjects with normal vision were trained for 3 weeks to read Braille exclusively by touch and scanned before and after training, while performing a same-different discrimination task on Braille characters and meaningless characters. Functional and diffusion-weighted magnetic resonance imaging sequences were used to assess resulting changes. The strongest training-induced effect was found in the primary somatosensory cortex (SI), where we observed bilateral augmentation in activity accompanied by an increase in fractional anisotropy (FA) within the contralateral SI. Increases of white matter fractional anisotropy were also observed in the secondary somatosensory area (SII) and the thalamus. Outside of somatosensory system, changes in both structure and function were found in i.e., the fusiform gyrus, the medial frontal gyri and the inferior parietal lobule. Our results provide evidence for functional remodeling of the somatosensory pathway and higher ordered multimodal brain areas occurring as a result of short-lasting tactile learning, and add to them a novel picture of extensive white matter plasticity.
Collapse
Affiliation(s)
- Weronika Debowska
- Laboratory of Neuroplasticity, Nencki Institute of Experimental Biology, Polish Academy of SciencesWarsaw, Poland; CNS Lab, Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of SciencesWarsaw, Poland
| | - Tomasz Wolak
- Bioimaging Research Center, World Hearing Center, The Institute of Physiology and Pathology of Hearing Warsaw, Poland
| | - Anna Nowicka
- Laboratory of Psychophysiology, Nencki Institute of Experimental Biology Warsaw, Poland
| | - Anna Kozak
- Department of Psychology, University of Social Sciences and Humanities Warsaw, Poland
| | - Marcin Szwed
- Department of Psychology, Jagiellonian University Cracow, Poland
| | - Malgorzata Kossut
- Laboratory of Neuroplasticity, Nencki Institute of Experimental Biology, Polish Academy of SciencesWarsaw, Poland; Department of Psychology, University of Social Sciences and HumanitiesWarsaw, Poland
| |
Collapse
|
27
|
Sathian K. Analysis of haptic information in the cerebral cortex. J Neurophysiol 2016; 116:1795-1806. [PMID: 27440247 DOI: 10.1152/jn.00546.2015] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 07/20/2016] [Indexed: 11/22/2022] Open
Abstract
Haptic sensing of objects acquires information about a number of properties. This review summarizes current understanding about how these properties are processed in the cerebral cortex of macaques and humans. Nonnoxious somatosensory inputs, after initial processing in primary somatosensory cortex, are partially segregated into different pathways. A ventrally directed pathway carries information about surface texture into parietal opercular cortex and thence to medial occipital cortex. A dorsally directed pathway transmits information regarding the location of features on objects to the intraparietal sulcus and frontal eye fields. Shape processing occurs mainly in the intraparietal sulcus and lateral occipital complex, while orientation processing is distributed across primary somatosensory cortex, the parietal operculum, the anterior intraparietal sulcus, and a parieto-occipital region. For each of these properties, the respective areas outside primary somatosensory cortex also process corresponding visual information and are thus multisensory. Consistent with the distributed neural processing of haptic object properties, tactile spatial acuity depends on interaction between bottom-up tactile inputs and top-down attentional signals in a distributed neural network. Future work should clarify the roles of the various brain regions and how they interact at the network level.
Collapse
Affiliation(s)
- K Sathian
- Departments of Neurology, Rehabilitation Medicine and Psychology, Emory University, Atlanta, Georgia; and Center for Visual and Neurocognitive Rehabilitation, Atlanta Department of Veterans Affairs Medical Center, Decatur, Georgia
| |
Collapse
|
28
|
Siuda-Krzywicka K, Bola Ł, Paplińska M, Sumera E, Jednoróg K, Marchewka A, Śliwińska MW, Amedi A, Szwed M. Massive cortical reorganization in sighted Braille readers. eLife 2016; 5:e10762. [PMID: 26976813 PMCID: PMC4805536 DOI: 10.7554/elife.10762] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 01/19/2016] [Indexed: 12/05/2022] Open
Abstract
The brain is capable of large-scale reorganization in blindness or after massive injury. Such reorganization crosses the division into separate sensory cortices (visual, somatosensory...). As its result, the visual cortex of the blind becomes active during tactile Braille reading. Although the possibility of such reorganization in the normal, adult brain has been raised, definitive evidence has been lacking. Here, we demonstrate such extensive reorganization in normal, sighted adults who learned Braille while their brain activity was investigated with fMRI and transcranial magnetic stimulation (TMS). Subjects showed enhanced activity for tactile reading in the visual cortex, including the visual word form area (VWFA) that was modulated by their Braille reading speed and strengthened resting-state connectivity between visual and somatosensory cortices. Moreover, TMS disruption of VWFA activity decreased their tactile reading accuracy. Our results indicate that large-scale reorganization is a viable mechanism recruited when learning complex skills. DOI:http://dx.doi.org/10.7554/eLife.10762.001 According to most textbooks, our brain is divided into separate areas that are dedicated to specific senses. We have a visual cortex for vision, a tactile cortex for touch, and so on. However, researchers suspect that this division might not be as fixed as the textbooks say. For example, blind people can switch their 'leftover' visual cortex to non-visual purposes, such as reading Braille – a tactile alphabet. Can this switch in functional organization also happen in healthy people with normal vision? To investigate this, Siuda-Krzywicka, Bola et al. taught a group of healthy, sighted people to read Braille by touch, and monitored the changes in brain activity that this caused using a technique called functional magnetic resonance imaging. According to textbooks, tactile reading should engage the tactile cortex. Yet, the experiment revealed that the brain activity critical for reading Braille by touch did not occur in the volunteers’ tactile cortex, but in their visual cortex. Further experiments used a technique called transcranial magnetic stimulation to suppress the activity of the visual cortex of the volunteers. This impaired their ability to read Braille by touch. This is a clear-cut proof that sighted adults can re-program their visual cortex for non-visual, tactile purposes. These results show that intensive training in a complex task can overcome the sensory division-of-labor of our brain. This indicates that our brain is much more flexible than previously thought, and that such flexibility might occur when we learn everyday, complex skills such as driving a car or playing a musical instrument. The next question that follows from this work is: what enables the brain’s activity to change after learning to read Braille? To understand this, Siuda-Krzywicka, Bola et al. are currently exploring how the physical structure of the brain changes as a result of a person acquiring the ability to read Braille by touch. DOI:http://dx.doi.org/10.7554/eLife.10762.002
Collapse
Affiliation(s)
- Katarzyna Siuda-Krzywicka
- Department of Psychology, Jagiellonian University, Kraków, Poland.,INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, and Université Pierre et Marie Curie-Paris 6, UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), Paris, France
| | - Łukasz Bola
- Department of Psychology, Jagiellonian University, Kraków, Poland.,Laboratory of Brain Imaging, Neurobiology Center, Nencki Institute of Experimental Biology, Warsaw, Poland
| | | | - Ewa Sumera
- Institute for the Blind and Partially Sighted Children in Krakow, Kraków, Poland
| | - Katarzyna Jednoróg
- Laboratory of Psychophysiology, Department of Neurophysiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Artur Marchewka
- Laboratory of Brain Imaging, Neurobiology Center, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Magdalena W Śliwińska
- Department of Experimental Psychology, University College London, London, United Kingdom
| | - Amir Amedi
- The Cognitive Science Program, The Hebrew University of Jerusalem, Jerusalem, Israel.,Department of Medical Neurobiology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.,The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.,Sorbonne Universite´s, UPMC Univ Paris 06, Institut de la Vision, Paris, France
| | - Marcin Szwed
- Department of Psychology, Jagiellonian University, Kraków, Poland
| |
Collapse
|
29
|
Bellucci G, Chernyak S, Hoffman M, Deshpande G, Dal Monte O, Knutson KM, Grafman J, Krueger F. Effective connectivity of brain regions underlying third-party punishment: Functional MRI and Granger causality evidence. Soc Neurosci 2016; 12:124-134. [PMID: 26942651 DOI: 10.1080/17470919.2016.1153518] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Third-party punishment (TPP) for norm violations is an essential deterrent in large-scale human societies, and builds on two essential cognitive functions: evaluating legal responsibility and determining appropriate punishment. Despite converging evidence that TPP is mediated by a specific set of brain regions, little is known about their effective connectivity (direction and strength of connections). Applying parametric event-related functional MRI in conjunction with multivariate Granger causality analysis, we asked healthy participants to estimate how much punishment a hypothetical perpetrator deserves for intentionally committing criminal offenses varying in levels of harm. Our results confirmed that TPP legal decisions are based on two domain-general networks: the mentalizing network for evaluating legal responsibility and the central-executive network for determining appropriate punishment. Further, temporal pole (TP) and dorsomedial prefrontal cortex (PFC) emerged as hubs of the mentalizing network, uniquely generating converging output connections to ventromedial PFC, temporo-parietal junction, and posterior cingulate. In particular, dorsomedial PFC received inputs only from TP and both its activation and its connectivity to dorsolateral PFC correlated with degree of punishment. This supports the hypothesis that dorsomedial PFC acts as the driver of the TPP activation pattern, leading to the decision on the appropriate punishment. In conclusion, these results advance our understanding of the organizational elements of the TPP brain networks and provide better insights into the mental states of judges and jurors tasked with blaming and punishing legal wrongs.
Collapse
Affiliation(s)
- Gabriele Bellucci
- a Molecular Neuroscience Department , George Mason University , Fairfax , VA , USA.,b Berlin School of Mind and Brain , Humboldt-Universitaet zu Berlin , Berlin , Germany
| | - Sergey Chernyak
- a Molecular Neuroscience Department , George Mason University , Fairfax , VA , USA
| | - Morris Hoffman
- c Second Judicial District , Denver , CO , USA.,d John D. and Catherine T. MacArthur Foundation's Research Network on Law and Neuroscience , Nashville , TN , USA
| | - Gopikrishna Deshpande
- e AU MRI Research Center, Department of Electrical and Computer Engineering , Auburn University , Auburn , AL , USA.,f Department of Psychology , Auburn University , Auburn , AL , USA
| | - Olga Dal Monte
- g Department of Psychology , Yale University , New Haven , CT , USA
| | - Kristine M Knutson
- h Behavioral Neurology Unit , National Institute of Neurological Disorders and Stroke, National Institutes of Health , Bethesda , MD , USA
| | - Jordan Grafman
- i Brain Injury Research Program , Rehabilitation Institute of Chicago , Chicago , IL , USA
| | - Frank Krueger
- a Molecular Neuroscience Department , George Mason University , Fairfax , VA , USA.,j Department of Psychology , George Mason University , Fairfax , VA , USA
| |
Collapse
|
30
|
Hampstead BM, Khoshnoodi M, Yan W, Deshpande G, Sathian K. Patterns of effective connectivity during memory encoding and retrieval differ between patients with mild cognitive impairment and healthy older adults. Neuroimage 2016; 124:997-1008. [PMID: 26458520 PMCID: PMC5619652 DOI: 10.1016/j.neuroimage.2015.10.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 09/09/2015] [Accepted: 10/01/2015] [Indexed: 01/04/2023] Open
Abstract
Previous research has shown that there is considerable overlap in the neural networks mediating successful memory encoding and retrieval. However, little is known about how the relevant human brain regions interact during these distinct phases of memory or how such interactions are affected by memory deficits that characterize mild cognitive impairment (MCI), a condition that often precedes dementia due to Alzheimer's disease. Here we employed multivariate Granger causality analysis using autoregressive modeling of inferred neuronal time series obtained by deconvolving the hemodynamic response function from measured blood oxygenation level-dependent (BOLD) time series data, in order to examine the effective connectivity between brain regions during successful encoding and/or retrieval of object location associations in MCI patients and comparable healthy older adults. During encoding, healthy older adults demonstrated a left hemisphere dominant pattern where the inferior frontal junction, anterior intraparietal sulcus (likely involving the parietal eye fields), and posterior cingulate cortex drove activation in most left hemisphere regions and virtually every right hemisphere region tested. These regions are part of a frontoparietal network that mediates top-down cognitive control and is implicated in successful memory formation. In contrast, in the MCI patients, the right frontal eye field drove activation in every left hemisphere region examined, suggesting reliance on more basic visual search processes. Retrieval in the healthy older adults was primarily driven by the right hippocampus with lesser contributions of the right anterior thalamic nuclei and right inferior frontal sulcus, consistent with theoretical models holding the hippocampus as critical for the successful retrieval of memories. The pattern differed in MCI patients, in whom the right inferior frontal junction and right anterior thalamus drove successful memory retrieval, reflecting the characteristic hippocampal dysfunction of these patients. These findings demonstrate that neural network interactions differ markedly between MCI patients and healthy older adults. Future efforts will investigate the impact of cognitive rehabilitation of memory on these connectivity patterns.
Collapse
Affiliation(s)
- B M Hampstead
- Rehabilitation R&D Center for Visual and Neurocognitive Rehabilitation, Atlanta VAMC, Decatur, GA 30033, USA; Department of Rehabilitation Medicine, Emory University, Atlanta, GA 30322, USA; VA Ann Arbor Healthcare System, Ann Arbor, MI 48105, USA; Department of Psychiatry, University of Michigan, Ann Arbor, MI 48105, USA.
| | - M Khoshnoodi
- Department of Neurology, Emory University, Atlanta, GA 30322, USA
| | - W Yan
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL 36830, USA
| | - G Deshpande
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL 36830, USA; Department of Psychology, Auburn University, Auburn, AL 36830, USA; Advanced Imaging Consortium, Auburn University and University of Alabama Birmingham, AL, USA
| | - K Sathian
- Rehabilitation R&D Center for Visual and Neurocognitive Rehabilitation, Atlanta VAMC, Decatur, GA 30033, USA; Department of Rehabilitation Medicine, Emory University, Atlanta, GA 30322, USA; Department of Neurology, Emory University, Atlanta, GA 30322, USA; Department of Psychology, Emory University, Atlanta, GA 30322, USA
| |
Collapse
|
31
|
Feng C, Deshpande G, Liu C, Gu R, Luo YJ, Krueger F. Diffusion of responsibility attenuates altruistic punishment: A functional magnetic resonance imaging effective connectivity study. Hum Brain Mapp 2015; 37:663-77. [PMID: 26608776 DOI: 10.1002/hbm.23057] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 10/16/2015] [Accepted: 11/06/2015] [Indexed: 11/11/2022] Open
Abstract
Humans altruistically punish violators of social norms to enforce cooperation and pro-social behaviors. However, such altruistic behaviors diminish when others are present, due to a diffusion of responsibility. We investigated the neural signatures underlying the modulations of diffusion of responsibility on altruistic punishment, conjoining a third-party punishment task with event-related functional magnetic resonance imaging and multivariate Granger causality mapping. In our study, participants acted as impartial third-party decision-makers and decided how to punish norm violations under two different social contexts: alone (i.e., full responsibility) or in the presence of putative other third-party decision makers (i.e., diffused responsibility). Our behavioral results demonstrated that the diffusion of responsibility served as a mediator of context-dependent punishment. In the presence of putative others, participants who felt less responsible also punished less severely in response to norm violations. Our neural results revealed that underlying this behavioral effect was a network of interconnected brain regions. For unfair relative to fair splits, the presence of others led to attenuated responses in brain regions implicated in signaling norm violations (e.g., AI) and to increased responses in brain regions implicated in calculating values of norm violations (e.g., vmPFC, precuneus) and mentalizing about others (dmPFC). The dmPFC acted as the driver of the punishment network, modulating target regions, such as AI, vmPFC, and precuneus, to adjust altruistic punishment behavior. Our results uncovered the neural basis of the influence of diffusion of responsibility on altruistic punishment and highlighted the role of the mentalizing network in this important phenomenon. Hum Brain Mapp 37:663-677, 2016. © 2015 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Chunliang Feng
- Institute of Affective and Social Neuroscience, School of Psychology and Sociology, Shenzhen University, Shenzhen, China.,State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
| | - Gopikrishna Deshpande
- Department of Electrical and Computer Engineering, Auburn University MRI Research Center, Auburn University, Auburn, Alabama.,Department of Psychology, Auburn University, Auburn, Alabama.,labama Advanced Imaging Consortium, Auburn University and University of Alabama Birmingham, Alabama
| | - Chao Liu
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
| | - Ruolei Gu
- Key Laboratory of Behavioral Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Yue-Jia Luo
- State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China.,Collaborative Innovation Center of Sichuan for Elder Care and Health, Chengdu Medical College, Chengdu, China
| | - Frank Krueger
- Molecular Neuroscience Department, George Mason University, Fairfax, Virginia.,Department of Psychology, George Mason University, Fairfax, Virginia
| |
Collapse
|
32
|
Schlaffke L, Rüther NN, Heba S, Haag LM, Schultz T, Rosengarth K, Tegenthoff M, Bellebaum C, Schmidt-Wilcke T. From perceptual to lexico-semantic analysis--cortical plasticity enabling new levels of processing. Hum Brain Mapp 2015; 36:4512-28. [PMID: 26304153 PMCID: PMC5049624 DOI: 10.1002/hbm.22939] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 07/23/2015] [Accepted: 07/30/2015] [Indexed: 11/09/2022] Open
Abstract
Certain kinds of stimuli can be processed on multiple levels. While the neural correlates of different levels of processing (LOPs) have been investigated to some extent, most of the studies involve skills and/or knowledge already present when performing the task. In this study we specifically sought to identify neural correlates of an evolving skill that allows the transition from perceptual to a lexico‐semantic stimulus analysis. Eighteen participants were trained to decode 12 letters of Morse code that were presented acoustically inside and outside of the scanner environment. Morse code was presented in trains of three letters while brain activity was assessed with fMRI. Participants either attended to the stimulus length (perceptual analysis), or evaluated its meaning distinguishing words from nonwords (lexico‐semantic analysis). Perceptual and lexico‐semantic analyses shared a mutual network comprising the left premotor cortex, the supplementary motor area (SMA) and the inferior parietal lobule (IPL). Perceptual analysis was associated with a strong brain activation in the SMA and the superior temporal gyrus bilaterally (STG), which remained unaltered from pre and post training. In the lexico‐semantic analysis post learning, study participants showed additional activation in the left inferior frontal cortex (IFC) and in the left occipitotemporal cortex (OTC), regions known to be critically involved in lexical processing. Our data provide evidence for cortical plasticity evolving with a learning process enabling the transition from perceptual to lexico‐semantic stimulus analysis. Importantly, the activation pattern remains task‐related LOP and is thus the result of a decision process as to which LOP to engage in. Hum Brain Mapp 36:4512–4528, 2015. © 2015 The Authors. Human Brain Mapping Published byWiley Periodicals, Inc.
Collapse
Affiliation(s)
- Lara Schlaffke
- Department of Neurology, BG-University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
| | - Naima N Rüther
- Department of Neuropsychology, Ruhr-University Bochum, Bochum, Germany
| | - Stefanie Heba
- Department of Neurology, BG-University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
| | - Lauren M Haag
- Department of Neurology, BG-University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
| | - Thomas Schultz
- Department of Computer Science, University of Bonn, Germany
| | | | - Martin Tegenthoff
- Department of Neurology, BG-University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
| | - Christian Bellebaum
- Department of Neuropsychology, Ruhr-University Bochum, Bochum, Germany.,Department of Psychology, Heinrich-Heine University Düsseldorf, Germany
| | - Tobias Schmidt-Wilcke
- Department of Neurology, BG-University Hospital Bergmannsheil, Ruhr-University Bochum, Bochum, Germany
| |
Collapse
|
33
|
Sreenivasan KR, Havlicek M, Deshpande G. Nonparametric hemodynamic deconvolution of FMRI using homomorphic filtering. IEEE TRANSACTIONS ON MEDICAL IMAGING 2015; 34:1155-1163. [PMID: 25531878 DOI: 10.1109/tmi.2014.2379914] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Functional magnetic resonance imaging (fMRI) is an indirect measure of neural activity which is modeled as a convolution of the latent neuronal response and the hemodynamic response function (HRF). Since the sources of HRF variability can be nonneural in nature, the measured fMRI signal does not faithfully represent underlying neural activity. Therefore, it is advantageous to deconvolve the HRF from the fMRI signal. However, since both latent neural activity and the voxel-specific HRF is unknown, the deconvolution must be blind. Existing blind deconvolution approaches employ highly parameterized models, and it is unclear whether these models have an over fitting problem. In order to address these issues, we 1) present a nonparametric deconvolution method based on homomorphic filtering to obtain the latent neuronal response from the fMRI signal and, 2) compare our approach to the best performing existing parametric model based on the estimation of the biophysical hemodynamic model using the Cubature Kalman Filter/Smoother. We hypothesized that if the results from nonparametric deconvolution closely resembled that obtained from parametric deconvolution, then the problem of over fitting during estimation in highly parameterized deconvolution models of fMRI could possibly be over stated. Both simulations and experimental results demonstrate support for our hypothesis since the estimated latent neural response from both parametric and nonparametric methods were highly correlated in the visual cortex. Further, simulations showed that both methods were effective in recovering the simulated ground truth of the latent neural response.
Collapse
|
34
|
Hutcheson NL, Sreenivasan KR, Deshpande G, Reid MA, Hadley J, White DM, Ver Hoef L, Lahti AC. Effective connectivity during episodic memory retrieval in schizophrenia participants before and after antipsychotic medication. Hum Brain Mapp 2014; 36:1442-57. [PMID: 25504918 DOI: 10.1002/hbm.22714] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 11/07/2014] [Accepted: 12/01/2014] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Impairment in episodic memory is one of the most robust findings in schizophrenia. Disruptions of fronto-temporal functional connectivity that could explain some aspects of these deficits have been reported. Recent work has identified abnormal hippocampal function in unmedicated patients with schizophrenia (SZ), such as increased metabolism and glutamate content that are not always seen in medicated SZ. For these reasons, we hypothesized that altered fronto-temporal connectivity might originate from the hippocampus and might be partially restored by antipsychotic medication. METHODS Granger causality methods were used to evaluate the effective connectivity between frontal and temporal regions in 21 unmedicated SZ and 20 matched healthy controls (HC) during performance of an episodic memory retrieval task. In 16 SZ, effective connectivity between these regions was evaluated before and after 1-week of antipsychotic treatment. RESULTS In HC, significant effective connectivity originating from the right hippocampus to frontal regions was identified. Compared to HC, unmedicated SZ showed significant altered fronto-temporal effective connectivity, including reduced right hippocampal to right medial frontal connectivity. After 1-week of antipsychotic treatment, connectivity more closely resembled the patterns observed in HC, including increased effective connectivity from the right hippocampus to frontal regions. CONCLUSIONS These results support the notion that memory disruption in schizophrenia might originate from hippocampal dysfunction and that medication restores some aspects of fronto-temporal dysconnectivity. Patterns of fronto-temporal connectivity could provide valuable biomarkers to identify new treatments for the symptoms of schizophrenia, including memory deficits.
Collapse
Affiliation(s)
- Nathan L Hutcheson
- Department of Psychiatry and Behavioral Neurobiology, The University of Alabama at Birmingham, Birmingham, Alabama
| | | | | | | | | | | | | | | |
Collapse
|
35
|
Eck J, Kaas AL, Mulders JL, Hausfeld L, Kourtzi Z, Goebel R. The Effect of Task Instruction on Haptic Texture Processing: The Neural Underpinning of Roughness and Spatial Density Perception. Cereb Cortex 2014; 26:384-401. [PMID: 25491119 DOI: 10.1093/cercor/bhu294] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Perceived roughness is associated with a variety of physical factors and multiple peripheral afferent types. The current study investigated whether this complexity of the mapping between physical and perceptual space is reflected at the cortical level. In an integrative psychophysical and imaging approach, we used dot pattern stimuli for which previous studies reported a simple linear relationship of interdot spacing and perceived spatial density and a more complex function of perceived roughness. Thus, by using both a roughness and a spatial estimation task, the physical and perceived stimulus characteristics could be dissociated, with the spatial density task controlling for the processing of low-level sensory aspects. Multivoxel pattern analysis was used to investigate which brain regions hold information indicative of the level of the perceived texture characteristics. While information about differences in perceived roughness was primarily available in higher-order cortices, that is, the operculo-insular cortex and a ventral visual cortex region, information about perceived spatial density could already be derived from early somatosensory and visual regions. This result indicates that cortical processing reflects the different complexities of the evaluated haptic texture dimensions. Furthermore, this study is to our knowledge the first to show a contribution of the visual cortex to tactile roughness perception.
Collapse
Affiliation(s)
- Judith Eck
- Department of Cognitive Neuroscience, Maastricht University, The Netherlands.,Brain Innovation B.V., Maastricht, The Netherlands
| | - Amanda L Kaas
- Department of Cognitive Neuroscience, Maastricht University, The Netherlands
| | | | - Lars Hausfeld
- Department of Cognitive Neuroscience, Maastricht University, The Netherlands
| | - Zoe Kourtzi
- Department of Psychology, University of Cambridge, Cambridge, UK
| | - Rainer Goebel
- Department of Cognitive Neuroscience, Maastricht University, The Netherlands.,Brain Innovation B.V., Maastricht, The Netherlands.,Netherlands Institute for Neuroscience, Institute of the Royal Netherlands Academy of Arts and Sciences (KNAW), Amsterdam, The Netherlands
| |
Collapse
|
36
|
Haag LM, Heba S, Lenz M, Glaubitz B, Höffken O, Kalisch T, Puts NA, Edden RAE, Tegenthoff M, Dinse H, Schmidt-Wilcke T. Resting BOLD fluctuations in the primary somatosensory cortex correlate with tactile acuity. Cortex 2014; 64:20-8. [PMID: 25461704 DOI: 10.1016/j.cortex.2014.09.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 08/08/2014] [Accepted: 09/26/2014] [Indexed: 01/21/2023]
Abstract
Sensory perception, including 2-point discrimination (2 ptD), is tightly linked to cortical processing of tactile stimuli in primary somatosensory cortices. While the role of cortical activity in response to a tactile stimulus has been widely investigated, the role of baseline cortical activity is largely unknown. Using resting state fMRI we investigated the relationship between local BOLD fluctuations in the primary somatosensory cortex (the representational field of the hand) and 2 ptD of the corresponding index finger (right and left). Cortical activity was measured using fractional amplitudes of the low frequency BOLD fluctuations (fALFF) and synchronicity using regional homogeneity (ReHo) of the S1 hand region during rest. 2 ptD correlated with higher ReHo values in the representational areas of the contralateral S1 cortex (left hand: p = .028; right hand: p = .049). 2 ptD additionally correlated with higher fALFF in the representational area of the left hand (p = .007) and showed a trend for a significant correlation in the representational area of the right hand (p = .051). Thus, higher BOLD amplitudes and synchronicity at rest, as measures of cortical activity and synchronicity, respectively, are related to better tactile discrimination abilities of the contralateral hand. Our findings extend the relationship seen between spontaneous BOLD fluctuations and sensory perception.
Collapse
Affiliation(s)
- Lauren M Haag
- Department of Neurology, BG-University Clinic Bergmannsheil, Ruhr University Bochum, Bochum, Germany.
| | - Stefanie Heba
- Department of Neurology, BG-University Clinic Bergmannsheil, Ruhr University Bochum, Bochum, Germany.
| | - Melanie Lenz
- Department of Neurology, BG-University Clinic Bergmannsheil, Ruhr University Bochum, Bochum, Germany.
| | - Benjamin Glaubitz
- Department of Neurology, BG-University Clinic Bergmannsheil, Ruhr University Bochum, Bochum, Germany.
| | - Oliver Höffken
- Department of Neurology, BG-University Clinic Bergmannsheil, Ruhr University Bochum, Bochum, Germany.
| | - Tobias Kalisch
- Institute of Neuroinformatics, Ruhr University Bochum, Bochum, Germany.
| | - Nicholaas A Puts
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
| | - Richard A E Edden
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
| | - Martin Tegenthoff
- Department of Neurology, BG-University Clinic Bergmannsheil, Ruhr University Bochum, Bochum, Germany.
| | - Hubert Dinse
- Institute of Neuroinformatics, Ruhr University Bochum, Bochum, Germany.
| | - Tobias Schmidt-Wilcke
- Department of Neurology, BG-University Clinic Bergmannsheil, Ruhr University Bochum, Bochum, Germany.
| |
Collapse
|
37
|
Wheelock MD, Sreenivasan KR, Wood KH, Ver Hoef LW, Deshpande G, Knight DC. Threat-related learning relies on distinct dorsal prefrontal cortex network connectivity. Neuroimage 2014; 102 Pt 2:904-12. [PMID: 25111474 DOI: 10.1016/j.neuroimage.2014.08.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 07/23/2014] [Accepted: 08/02/2014] [Indexed: 10/24/2022] Open
Abstract
Conditioned changes in the emotional response to threat (e.g. aversive unconditioned stimulus; UCS) are mediated in part by the prefrontal cortex (PFC). Unpredictable threats elicit large emotional responses, while the response is diminished when the threat is predictable. A better understanding of how PFC connectivity to other brain regions varies with threat predictability would provide important insights into the neural processes that mediate conditioned diminution of the emotional response to threat. The present study examined brain connectivity during predictable and unpredictable threat exposure using a fear conditioning paradigm (previously published in Wood et al., 2012) in which unconditioned functional magnetic resonance imaging data were reanalyzed to assess effective connectivity. Granger causality analysis was performed using the time series data from 15 activated regions of interest after hemodynamic deconvolution, to determine regional effective connectivity. In addition, connectivity path weights were correlated with trait anxiety measures to assess the relationship between negative affect and brain connectivity. Results indicate the dorsomedial PFC (dmPFC) serves as a neural hub that influences activity in other brain regions when threats are unpredictable. In contrast, the dorsolateral PFC (dlPFC) serves as a neural hub that influences the activity of other brain regions when threats are predictable. These findings are consistent with the view that the dmPFC coordinates brain activity to take action, perhaps in a reactive manner, when an unpredicted threat is encountered, while the dlPFC coordinates brain regions to take action, in what may be a more proactive manner, to respond to predictable threats. Further, dlPFC connectivity to other brain regions (e.g. ventromedial PFC, amygdala, and insula) varied with negative affect (i.e. trait anxiety) when the UCS was predictable, suggesting that stronger connectivity may be required for emotion regulation in individuals with higher levels of negative affect.
Collapse
Affiliation(s)
- M D Wheelock
- Department of Psychology, University of Alabama at Birmingham, USA
| | - K R Sreenivasan
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, USA
| | - K H Wood
- Department of Psychology, University of Alabama at Birmingham, USA
| | - L W Ver Hoef
- Department of Neurology, University of Alabama at Birmingham, School of Medicine, Birmingham VA Medical Center, USA
| | - Gopikrishna Deshpande
- AU MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, Auburn, AL, USA; Department of Psychology, Auburn University, Auburn, AL, USA
| | - D C Knight
- Department of Psychology, University of Alabama at Birmingham, USA.
| |
Collapse
|
38
|
Lacey S, Sathian K. Visuo-haptic multisensory object recognition, categorization, and representation. Front Psychol 2014; 5:730. [PMID: 25101014 PMCID: PMC4102085 DOI: 10.3389/fpsyg.2014.00730] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 06/23/2014] [Indexed: 12/15/2022] Open
Abstract
Visual and haptic unisensory object processing show many similarities in terms of categorization, recognition, and representation. In this review, we discuss how these similarities contribute to multisensory object processing. In particular, we show that similar unisensory visual and haptic representations lead to a shared multisensory representation underlying both cross-modal object recognition and view-independence. This shared representation suggests a common neural substrate and we review several candidate brain regions, previously thought to be specialized for aspects of visual processing, that are now known also to be involved in analogous haptic tasks. Finally, we lay out the evidence for a model of multisensory object recognition in which top-down and bottom-up pathways to the object-selective lateral occipital complex are modulated by object familiarity and individual differences in object and spatial imagery.
Collapse
Affiliation(s)
- Simon Lacey
- Department of Neurology, Emory University School of Medicine Atlanta, GA, USA
| | - K Sathian
- Department of Neurology, Emory University School of Medicine Atlanta, GA, USA ; Department of Rehabilitation Medicine, Emory University School of Medicine Atlanta, GA, USA ; Department of Psychology, Emory University School of Medicine Atlanta, GA, USA ; Rehabilitation Research and Development Center of Excellence, Atlanta Veterans Affairs Medical Center Decatur, GA, USA
| |
Collapse
|
39
|
Sabatinelli D, Frank DW, Wanger TJ, Dhamala M, Adhikari BM, Li X. The timing and directional connectivity of human frontoparietal and ventral visual attention networks in emotional scene perception. Neuroscience 2014; 277:229-38. [PMID: 25018086 DOI: 10.1016/j.neuroscience.2014.07.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 07/01/2014] [Accepted: 07/02/2014] [Indexed: 12/12/2022]
Abstract
Electrocortical and hemodynamic measures reliably identify enhanced activity in the ventral and dorsal visual cortices during the perception of emotionally arousing versus neutral images, an effect that may reflect directive feedback from the subcortical amygdala. However, other brain regions strongly modulate visual attention, such as frontal eye fields (FEF) and intraparietal sulcus (IPS). Here we employ rapid sampling of BOLD signal (4 Hz) in the amygdala, fusiform gyrus (FG), FEF and IPS in 42 human participants as they viewed a series of emotional and neutral natural scene photographs balanced for luminosity and complexity, to test whether emotional discrimination is evident in dorsal structures prior to such discrimination in the amygdala and FG. Granger causality analyses were used to assess directional connectivity within dorsal and ventral networks. Results demonstrate emotionally-enhanced peak BOLD signal in the amygdala, FG, FEF, and IPS, with the onset of BOLD signal discrimination occurring between 2 and 3s after stimulus onset in ventral structures, and between 4 and 5s in FEF and IPS. Granger causality estimates yield stronger directional connectivity from IPS to FEF than the reverse in this emotional picture paradigm. Consistent with a reentrant perspective of emotional scene perception, greater directional connectivity was found from the amygdala to FG compared to the reverse. These data support a perspective in which the registration of emotional scene content is orchestrated by the amygdala and rostral inferotemporal visual cortex.
Collapse
Affiliation(s)
- D Sabatinelli
- Department of Psychology & Neuroscience, BioImaging Research Center, University of Georgia, Athens, GA 30602, United States.
| | - D W Frank
- Department of Psychology & Neuroscience, BioImaging Research Center, University of Georgia, Athens, GA 30602, United States
| | - T J Wanger
- Department of Psychology & Neuroscience, BioImaging Research Center, University of Georgia, Athens, GA 30602, United States
| | - M Dhamala
- Department of Physics & Astronomy, Neuroscience Institute, Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30302, United States
| | - B M Adhikari
- Department of Physics & Astronomy, Neuroscience Institute, Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA 30302, United States
| | - X Li
- Department of Computer Science, BioImaging Research Center, University of Georgia, Athens, GA 30602, United States
| |
Collapse
|
40
|
Lacey S, Stilla R, Sreenivasan K, Deshpande G, Sathian K. Spatial imagery in haptic shape perception. Neuropsychologia 2014; 60:144-58. [PMID: 25017050 DOI: 10.1016/j.neuropsychologia.2014.05.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 04/27/2014] [Accepted: 05/13/2014] [Indexed: 12/14/2022]
Abstract
We have proposed that haptic activation of the shape-selective lateral occipital complex (LOC) reflects a model of multisensory object representation in which the role of visual imagery is modulated by object familiarity. Supporting this, a previous functional magnetic resonance imaging (fMRI) study from our laboratory used inter-task correlations of blood oxygenation level-dependent (BOLD) signal magnitude and effective connectivity (EC) patterns based on the BOLD signals to show that the neural processes underlying visual object imagery (objIMG) are more similar to those mediating haptic perception of familiar (fHS) than unfamiliar (uHS) shapes. Here we employed fMRI to test a further hypothesis derived from our model, that spatial imagery (spIMG) would evoke activation and effective connectivity patterns more related to uHS than fHS. We found that few of the regions conjointly activated by spIMG and either fHS or uHS showed inter-task correlations of BOLD signal magnitudes, with parietal foci featuring in both sets of correlations. This may indicate some involvement of spIMG in HS regardless of object familiarity, contrary to our hypothesis, although we cannot rule out alternative explanations for the commonalities between the networks, such as generic imagery or spatial processes. EC analyses, based on inferred neuronal time series obtained by deconvolution of the hemodynamic response function from the measured BOLD time series, showed that spIMG shared more common paths with uHS than fHS. Re-analysis of our previous data, using the same EC methods as those used here, showed that, by contrast, objIMG shared more common paths with fHS than uHS. Thus, although our model requires some refinement, its basic architecture is supported: a stronger relationship between spIMG and uHS compared to fHS, and a stronger relationship between objIMG and fHS compared to uHS.
Collapse
Affiliation(s)
- Simon Lacey
- Department of Neurology, Emory University, Atlanta, GA, USA
| | - Randall Stilla
- Department of Neurology, Emory University, Atlanta, GA, USA
| | - Karthik Sreenivasan
- AU MRI Research Center, Department of Electrical & Computer Engineering, Auburn University, Auburn, AL, USA
| | - Gopikrishna Deshpande
- AU MRI Research Center, Department of Electrical & Computer Engineering, Auburn University, Auburn, AL, USA; Department of Psychology, Auburn University, Auburn, AL, USA
| | - K Sathian
- Department of Neurology, Emory University, Atlanta, GA, USA; Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA; Department of Psychology, Emory University, Atlanta, GA, USA; Rehabilitation R&D Center of Excellence, Atlanta VAMC, Decatur, GA, USA.
| |
Collapse
|
41
|
Reuter EM, Voelcker-Rehage C, Vieluf S, Godde B. Effects of age and expertise on tactile learning in humans. Eur J Neurosci 2014; 40:2589-99. [DOI: 10.1111/ejn.12629] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 04/02/2013] [Accepted: 04/22/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Eva-Maria Reuter
- Jacobs Center on Lifelong Learning and Institutional Development; Jacobs University Bremen; Bremen Germany
| | - Claudia Voelcker-Rehage
- Jacobs Center on Lifelong Learning and Institutional Development; Jacobs University Bremen; Bremen Germany
- AGEACT Research Center; Jacobs University Bremen; Bremen Germany
| | - Solveig Vieluf
- Jacobs Center on Lifelong Learning and Institutional Development; Jacobs University Bremen; Bremen Germany
- Aix-Marseille Université; CNRS; ISM UMR; Marseille France
| | - Ben Godde
- Jacobs Center on Lifelong Learning and Institutional Development; Jacobs University Bremen; Bremen Germany
- AGEACT Research Center; Jacobs University Bremen; Bremen Germany
| |
Collapse
|
42
|
Adhikari BM, Sathian K, Epstein CM, Lamichhane B, Dhamala M. Oscillatory activity in neocortical networks during tactile discrimination near the limit of spatial acuity. Neuroimage 2014; 91:300-10. [PMID: 24434679 DOI: 10.1016/j.neuroimage.2014.01.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 12/20/2013] [Accepted: 01/03/2014] [Indexed: 12/11/2022] Open
Abstract
Oscillatory interactions within functionally specialized but distributed brain regions are believed to be central to perceptual and cognitive functions. Here, using human scalp electroencephalography (EEG) recordings combined with source reconstruction techniques, we study how oscillatory activity functionally organizes different neocortical regions during a tactile discrimination task near the limit of spatial acuity. While undergoing EEG recordings, blindfolded participants felt a linear three-dot array presented electromechanically, under computer control, and reported whether the central dot was offset to the left or right. The average brain response differed significantly for trials with correct and incorrect perceptual responses in the timeframe approximately between 130 and 175ms. During trials with correct responses, source-level peak activity appeared in the left primary somatosensory cortex (SI) at around 45ms, in the right lateral occipital complex (LOC) at 130ms, in the right posterior intraparietal sulcus (pIPS) at 160ms, and finally in the left dorsolateral prefrontal cortex (dlPFC) at 175ms. Spectral interdependency analysis of activity in these nodes showed two distinct distributed networks, a dominantly feedforward network in the beta band (12-30Hz) that included all four nodes and a recurrent network in the gamma band (30-100Hz) that linked SI, pIPS and dlPFC. Measures of network activity in both bands were correlated with the accuracy of task performance. These findings suggest that beta and gamma band oscillatory networks coordinate activity between neocortical regions mediating sensory and cognitive processing to arrive at tactile perceptual decisions.
Collapse
Affiliation(s)
- Bhim M Adhikari
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA, USA
| | - K Sathian
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA; Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA; Department of Psychology, Emory University, Atlanta, GA, USA; Rehabilitation R&D Center of Excellence, Atlanta VAMC, Decatur, GA, USA
| | - Charles M Epstein
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, USA
| | - Bidhan Lamichhane
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA, USA
| | - Mukesh Dhamala
- Department of Physics and Astronomy, Georgia State University, Atlanta, GA, USA; Neuroscience Institute, Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, USA.
| |
Collapse
|
43
|
A physical constraint on perceptual learning: tactile spatial acuity improves with training to a limit set by finger size. J Neurosci 2013; 33:9345-52. [PMID: 23719803 DOI: 10.1523/jneurosci.0514-13.2013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In touch as in vision, perceptual acuity improves with training to an extent that differs greatly across people; even individuals with similar initial acuity may undergo markedly different improvement with training. What accounts for this variability in perceptual learning? We hypothesized that a simple physical characteristic, fingertip surface area, might constrain tactile learning, because previous research suggests that larger fingers have more widely spaced mechanoreceptors. To test our hypothesis, we trained 10 human participants intensively on a tactile spatial acuity task. During 4 d, participants completed 1900 training trials (38 50-trial blocks) in which they discriminated the orientation of square-wave gratings pressed onto the stationary index or ring finger, with auditory feedback provided to signal correct and incorrect responses. We progressively increased task difficulty by shifting to thinner groove widths whenever participants achieved ≥90% correct block performance. We took optical scans to measure surface area from the distal interphalangeal crease to the tip of the finger. Participants' acuity improved markedly on the trained finger and to a lesser extent on the untrained finger. Crucially, we found that participants' tactile spatial acuity improved toward a theoretical optimum set by their finger size; participants with worse initial performance relative to their finger size improved more with training, and posttraining performance was better correlated than pretraining performance with finger size. These results strongly support the hypothesis that tactile perceptual learning is limited by finger size. We suspect that analogous physical constraints on perceptual learning will be found in other sensory modalities.
Collapse
|
44
|
Omrani M, Lak A, Diamond ME. Learning not to feel: reshaping the resolution of tactile perception. Front Syst Neurosci 2013; 7:29. [PMID: 23847478 PMCID: PMC3701118 DOI: 10.3389/fnsys.2013.00029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 06/14/2013] [Indexed: 11/13/2022] Open
Abstract
We asked whether biased feedback during training could cause human subjects to lose perceptual acuity in a vibrotactile frequency discrimination task. Prior to training, we determined each subject's vibration frequency discrimination capacity on one fingertip, the Just Noticeable Difference (JND). Subjects then received 850 trials in which they performed a same/different judgment on two vibrations presented to that fingertip. They gained points whenever their judgment matched the computer-generated feedback on that trial. Feedback, however, was biased: the probability per trial of “same” feedback was drawn from a normal distribution with standard deviation twice as wide as the subject's JND. After training, the JND was significantly widened: stimulus pairs previously perceived as different were now perceived as the same. The widening of the JND extended to the untrained hand, indicating that the decrease in resolution originated in non-topographic brain regions. In sum, the acuity of subjects' sensory-perceptual systems shifted in order to match the feedback received during training.
Collapse
Affiliation(s)
- Mohsen Omrani
- Tactile Perception and Learning Lab, International School for Advanced Studies-SISSA Trieste, Italy ; School of Cognitive Sciences, Institute for Research in Fundamental Sciences (IPM) Tehran, Iran ; Centre for Neuroscience Studies, Queen's University Kingston, ON, Canada
| | | | | |
Collapse
|