title: Transcranial magnetic stimulation of posterior parietal cortex affects decisions of hand choice.
abstract: Deciding which hand to use for an action is one of the most frequent decisions people make in everyday behavior. Using a speeded reaching task, we provide evidence that hand choice entails a competitive decision process between simultaneously activated action plans for each hand. We then show that single-pulse transcranial magnetic stimulation to the left posterior parietal cortex biases this competitive process, leading to an increase in ipsilateral, left hand reaches. Stimulation of the right posterior parietal cortex did not alter hand choice, suggesting a hemispheric asymmetry in the representations of reach plans. These results are unique in providing causal evidence that the posterior parietal cortex is involved in decisions of hand choice.
authors.affiliation: Department of Psychology and Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720, USA. oflavio@gmail.com
authors.forename: Flavio T P
authors.initials: FT
authors.lastname: Oliveira
authors.forename: Jörn
authors.initials: J
authors.lastname: Diedrichsen
authors.forename: Timothy
authors.initials: T
authors.lastname: Verstynen
authors.forename: Julie
authors.initials: J
authors.lastname: Duque
authors.forename: Richard B
authors.initials: RB
authors.lastname: Ivry
mesh_terms: D000328:Adult; D002755:Choice Behavior / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006225:Hand / Q000502:physiology*; D006801:Humans; D010296:Parietal Lobe / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation