title: Polarity-Dependent Misperception of Subjective Visual Vertical during and after Transcranial Direct Current Stimulation (tDCS).
abstract: Pathologic tilt of subjective visual vertical (SVV) frequently has adverse functional consequences for patients with stroke and vestibular disorders. Repetitive transcranial magnetic stimulation (rTMS) of the supramarginal gyrus can produce a transitory tilt on SVV in healthy subjects. However, the effect of transcranial direct current stimulation (tDCS) on SVV has never been systematically studied. We investigated whether bilateral tDCS over the temporal-parietal region could result in both online and offline SVV misperception in healthy subjects. In a randomized, sham-controlled, single-blind crossover pilot study, thirteen healthy subjects performed tests of SVV before, during and after the tDCS applied over the temporal-parietal region in three conditions used on different days: right anode/left cathode; right cathode/left anode; and sham. Subjects were blind to the tDCS conditions. Montage-specific current flow patterns were investigated using computational models. SVV was significantly displaced towards the anode during both active stimulation conditions when compared to sham condition. Immediately after both active conditions, there were rebound effects. Longer lasting after-effects towards the anode occurred only in the right cathode/left anode condition. Current flow models predicted the stimulation of temporal-parietal regions under the electrodes and deep clusters in the posterior limb of the internal capsule. The present findings indicate that tDCS over the temporal-parietal region can significantly alter human SVV perception. This tDCS approach may be a potential clinical tool for the treatment of SVV misperception in neurological patients.
authors.affiliation: Department of Neuroscience and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
authors.forename: Taiza E G
authors.initials: TE
authors.lastname: Santos-Pontelli
authors.affiliation: Department of Neuroscience and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
authors.forename: Brunna P
authors.initials: BP
authors.lastname: Rimoli
authors.affiliation: Department of Neuroscience and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
authors.forename: Diandra B
authors.initials: DB
authors.lastname: Favoretto
authors.affiliation: Department of Neuroscience and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
authors.forename: Suleimy C
authors.initials: SC
authors.lastname: Mazin
authors.affiliation: Neural Engineering Laboratory, Department of Biomedical Engineering, The City College of New York of the City University of New York, New York, New York, United States of America.
authors.forename: Dennis Q
authors.initials: DQ
authors.lastname: Truong
authors.affiliation: Department of Neuroscience and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
authors.forename: Joao P
authors.initials: JP
authors.lastname: Leite
authors.affiliation: Department of Neuroscience and Behavioral Sciences, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, Brazil.
authors.forename: Octavio M
authors.initials: OM
authors.lastname: Pontes-Neto
authors.affiliation: Non-invasive Brain Stimulation and Human Motor Control Laboratory, Burke Medical Research Institute, White Plains, New York, United States of America; Neurology Department, Weill Medical College, Cornell University, New York, New York, United States of America.
authors.forename: Suzanne R
authors.initials: SR
authors.lastname: Babyar
authors.affiliation: Non-invasive Brain Stimulation and Human Motor Control Laboratory, Burke Medical Research Institute, White Plains, New York, United States of America; Neurology Department, Weill Medical College, Cornell University, New York, New York, United States of America.
authors.forename: Michael
authors.initials: M
authors.lastname: Reding
authors.affiliation: Neural Engineering Laboratory, Department of Biomedical Engineering, The City College of New York of the City University of New York, New York, New York, United States of America.
authors.forename: Marom
authors.initials: M
authors.lastname: Bikson
authors.affiliation: Non-invasive Brain Stimulation and Human Motor Control Laboratory, Burke Medical Research Institute, White Plains, New York, United States of America; Neurology Department, Weill Medical College, Cornell University, New York, New York, United States of America.
authors.forename: Dylan J
authors.initials: DJ
authors.lastname: Edwards
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology; D004566:Electrodes; D005260:Female; D020342:Finite Element Analysis; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D065908:Transcranial Direct Current Stimulation; D014796:Visual Perception / Q000502:physiology*