Authors:
Arshad Q; Siddiqui S; Ramachandran S; Goga U; Bonsu A; Patel M ; Roberts RE; Nigmatullina Y; Malhotra P; Bronstein AM. Institution Arshad,Q. Division of Brain Sciences, Charing Cross Hospit al Campus, Imperial College, Fulham Palace Road, London W6 8RF, UK. Siddiqui,S. Division of Brain Sciences, Charing Cross Ho spital Campus, Imperial College, Fulham Palace Road, London W6 8RF, UK. Ramachandran,S. Division of Brain Sciences, Charing Cross Hosp ital Campus, Imperial College, Fulham Palace Road, London W6 8RF, UK. Goga,U. Division of Brain Sciences, Charing Cross Hospit al Campus, Imperial College, Fulham Palace Road, London W6 8RF, UK. Bonsu,A. Division of Brain Sciences, Charing Cross Hosp ital Campus, Imperial College, Fulham Palace Road, London W6 8RF, UK. Patel,M. Division of Brain Sciences, Charing Cross Hospi tal Campus, Imperial College, Fulham Palace Road, London W6 8RF, UK. Roberts,R E. Division of Brain Sciences, Charing Cross Hos pital Campus, Imperial College, Fulham Palace Road, London W6 8RF, UK. Nigmatullina,Y. Division of Brain Sciences, Charing Cross Hospital Campus, Imperial College, Fulham Palace Road, London W6 8RF, UK. Malhotra,P. Division of Brain Sciences, Charing Cross Hospit al Campus, Imperial College, Fulham Palace Road, London W6 8RF, UK. Bronstein,A M. Division of Brain Sciences, Charing Cross H ospital Campus, Imperial College, Fulham Palace Road, London W6 8RF, UK. Electronic address: a.bronstein@imperial.ac.uk.
Title:
Right hemisphere dominance directly predicts both baseline V1 cortical excitability and the degree of top-down modulation exerted ov er low-level brain structures.
Source: Neuroscience. 311:484-9, 2015 Dec 17.
Abstract: Right hemisphere dominance for visuo-spatial attention is characteristically observed in most right-handed individuals . This dominance has been attributed to both an anatomically larger ri ght fronto-parietal network and the existence of asymmetric parietal interhemispheric connections. Previously it has been demonstr ated that interhemispheric conflict, which induces left hemisphere inhi bition, results in the modulation of both (i) the excitability of the early visual cortex (V1) and (ii) the brainstem-mediated vestibular-ocular r eflex (VOR) via top-down control mechanisms. However to date, it remains u nknown whether the degree of an individual’s right hemisphere dominan ce for visuospatial function can influence, (i) the baseline excitab ility of the visual cortex and (ii) the extent to which the right hemisp here can exert top-down modulation. We directly tested this by correlatin g line bisection error (or pseudoneglect), taken as a measure of right hemisphere dominance, with both (i) visual cortical excitability mea sured using phosphene perception elicited via single-pulse occipital tr ans-cranial magnetic stimulation (TMS) and (ii) the degree of trans-cranial direct current stimulation (tDCS)-mediated VOR suppression, followin g left hemisphere inhibition. We found that those individuals wi th greater right hemisphere dominance had a less excitable early visual cortex at baseline and demonstrated a greater degree of vestibular nystagmus suppres sion following left hemisphere cathodal tDCS. To conclude, our r esults provide the first demonstration that individual differences in r ight hemisphere dominance can directly predict both the baseline excitability of low-level brain structures and the degree of top-down modulation ex erted over them.
Copyright © 2015 The Authors. Published by Elsevier Ltd. . All rights reserved.
Publication Type Journal Article.
