@article{1247b113b5eb437c923741418c8c5902,
title = "Visual responsiveness in sensorimotor cortex is increased following amputation and reduced after mirror therapy",
abstract = "Phantom limb pain (PLP) following amputation, which is experienced by the vast majority of amputees, has been reported to be relieved with daily sessions of mirror therapy. During each session, a mirror is used to view the reflected image of the intact limb moving, providing visual feedback consistent with the movement of the missing/phantom limb. To investigate potential neural correlates of the treatment effect, we measured brain responses in volunteers with unilateral leg amputation using functional magnetic resonance imaging (fMRI) during a four-week course of mirror therapy. Mirror therapy commenced immediately following baseline scans, which were repeated after approximately two and four week intervals. We focused on responses in the region of sensorimotor cortex corresponding to primary somatosensory and motor representations of the missing leg. At baseline, prior to starting therapy, we found a strong and unexpected response in sensorimotor cortex of amputees to visually presented images of limbs. This response was stronger for images of feet compared to hands and there was no such response in matched controls. Further, this response to visually presented limbs was no longer present at the end of the four week mirror therapy treatment, when perceived phantom limb pain was also reduced. A similar pattern of results was also observed in extrastriate and parietal regions typically responsive to viewing hand actions, but not in regions corresponding to secondary somatosensory cortex. Finally, there was a significant correlation between initial visual responsiveness in sensorimotor cortex and reduction in PLP suggesting a potential marker for predicting efficacy of mirror therapy. Thus, enhanced visual responsiveness in sensorimotor cortex is associated with PLP and modulated over the course of mirror therapy.",
keywords = "Amputation, Phantom limb pain, Sensorimotor, Vision, fMRI",
author = "Chan, {Annie W.Y.} and Emily Bilger and Sarah Griffin and Viktoria Elkis and Sharon Weeks and Lindsay Hussey-Anderson and Pasquina, {Paul F.} and Tsao, {Jack W.} and Baker, {Chris I.}",
note = "Funding Information: This study was supported by the intramural program of the National Institute of Mental Health (CIB), ZIA-MH-002893, the Postdoctoral Intramural Research Training Award in NIMH (AC), a grant from the David Mahoney Neuroimaging Program of the Dana Foundation (CIB, JWT), and the Center for Rehabilitation Sciences Research at the Uniformed Services University of the Health Sciences (PFP, JWT). We thank Dr. Howard Gilmer (National Rehabilitation Hospital, Washington, DC) for assistance with recruiting amputee participants, Beth Aguila and Marcie King for assistance with fMRI data collection, and Jennifer Henry for consolidating demographic data. We also thank members in the Laboratory and Brain Cognition (NIMH) for helpful discussions and comments on the study. Author contributions: Conceptualization, AC and CIB, with early input from JWT; Design and materials: AC and CIB; Data curation, AC and CIB; Formal analysis: AC and CIB; Investigation: AC and CIB; Methodology: AC and CIB; Recruitment: all authors contributed; Writing – review & editing AC, CIB, and JWT. Writing – original and final drafts: AC and CIB. The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or reflecting the views of the Department of the Navy or the Department of Defense. Funding Information: This study was supported by the intramural program of the National Institute of Mental Health (CIB), ZIA-MH-002893 , the Postdoctoral Intramural Research Training Award in NIMH (AC), a grant from the David Mahoney Neuroimaging Program of the Dana Foundation (CIB, JWT), and the Center for Rehabilitation Sciences Research at the Uniformed Services University of the Health Sciences (PFP, JWT). We thank Dr. Howard Gilmer (National Rehabilitation Hospital, Washington, DC) for assistance with recruiting amputee participants, Beth Aguila and Marcie King for assistance with fMRI data collection, and Jennifer Henry for consolidating demographic data. We also thank members in the Laboratory and Brain Cognition (NIMH) for helpful discussions and comments on the study. Author contributions: Conceptualization, AC and CIB, with early input from JWT; Design and materials: AC and CIB; Data curation, AC and CIB; Formal analysis: AC and CIB; Investigation: AC and CIB; Methodology: AC and CIB; Recruitment: all authors contributed; Writing – review & editing AC, CIB, and JWT. Writing – original and final drafts: AC and CIB. Publisher Copyright: {\textcopyright} 2019 The Authors",
year = "2019",
doi = "10.1016/j.nicl.2019.101882",
language = "English (US)",
volume = "23",
journal = "NeuroImage: Clinical",
issn = "2213-1582",
publisher = "Elsevier BV",
}