biostudies-literatureNandi TIntramural NIH HHSNIMH NIH HHSNational Institutes of HealthEuropean CommissionRoyal SocietyLundbeck FoundationUK Research and InnovationMedical Research CouncilNIHR Oxford Biomedical Research CentreHorizon 2020National Institute for Health Research (NIHR)National Institute for Health and Care ResearchLundbeckfondenWellcome Trust1153-1162https://www.ebi.ac.uk/biostudies/studies/S-EPMC7613675biostudies-literatureUnknown15(5)<h4>Background and objective</h4>Transcranial direct current stimulation (tDCS) has wide ranging applications in neuro-behavioural and physiological research, and in neurological rehabilitation. However, it is currently limited by substantial inter-subject variability in responses, which may be explained, at least in part, by anatomical differences that lead to variability in the electric field (E-field) induced in the cortex. Here, we tested whether the variability in the E-field in the stimulated cortex during anodal tDCS, estimated using computational simulations, explains the variability in tDCS induced changes in GABA, a neurophysiological marker of stimulation effect.<h4>Methods</h4>Data from five previously conducted MRS studies were combined. The anode was placed over the left primBrain stimulationtDCS induced GABA change is associated with the simulated electric field in M1, an effect mediated by grey matter volume in the MRS voxel.PMC7613675203139/Z/16/ZR244-2017-196102584731827ZIA-MH002781203139102584/Z/13/ZMR/W008939/1ZIA-MH002782110027/Z/15/ZNIHR-INF-1315RF1 MH117428ZIA MH002782R360-2021-3951RF1MH117428-01A1ZIA MH002781MC_UU_00003/4R313-2019-622Bachtiar VBerrington AJohansen-Berg HBarron HCJohnstone AKolasinski JPuonti OWinkler AMStagg CJClarke WTHinson ELHanayik TThielscher ANandi TNettekoven CfalsetDCS induced GABA change is associated with the simulated electric field in M1, an effect mediated by grey matter volume in the MRS voxel.<h4>Background and objective</h4>Transcranial direct current stimulation (tDCS) has wide ranging applications in neuro-behavioural and physiological research, and in neurological rehabilitation. However, it is currently limited by substantial inter-subject variability in responses, which may be explained, at least in part, by anatomical differences that lead to variability in the electric field (E-field) induced in the cortex. Here, we tested whether the variability in the E-field in the stimulated cortex during anodal tDCS, estimated using computational simulations, explains the variability in tDCS induced changes in GABA, a neurophysiological marker of stimulation effect.<h4>Methods</h4>Data from five previously conducted MRS studies were combined. The anode was placed over the left prim2022-01-01T00:00:00Z2022 Sep-Oct2025-04-04T02:25:59.757Z2024-11-19T16:21:29.335ZS-EPMC76136753598886210.1016/j.brs.2022.07.049