title: Interhemispheric transmission of visuomotor information for motor implementation.
abstract: Using transcranial magnetic stimulation (TMS), we addressed the contribution of both hemispheres to the visuomotor control of each hand. The subjects had to press one of two buttons as quickly as possible after the go-signal. A precue preceding this conveyed full, partial or no advance information (hand and/or button), such that reaction time (RT) shortened with increasing amount of information. We gave TMS over each hemisphere at various time intervals (100-350 ms) after the go-signal and before the expected onset of response, and measured its effect on RT, movement time (MT) and error rate. At short intervals (100-200 ms), left hemisphere TMS delayed RT and prolonged MT of both hands, while right hemisphere TMS delayed RT only of the right hand, without affecting error rates. At long intervals (250-350 ms), TMS produced slightly more pronounced RT delays of the contralateral hand. RT was delayed more if the precues were less informative. The results suggest the importance of interhemispheric transmission of visuomotor information for motor implementation. The right hemisphere may play a role mainly in calculating target and effector information, determining RT, while the left hemisphere may play a role in elaborating the motor program and determining MT.
authors.affiliation: Department of Neurology, Division of Neuroscience, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan 113-8655. yterao-tky@umin.ac.jp
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Terao
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Furubayashi
authors.forename: Shingo
authors.initials: S
authors.lastname: Okabe
authors.forename: Noritoshi
authors.initials: N
authors.lastname: Arai
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Mochizuki
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Masato
authors.initials: M
authors.lastname: Yumoto
authors.forename: Masami
authors.initials: M
authors.lastname: Nishikawa
authors.forename: Nobue K
authors.initials: NK
authors.lastname: Iwata
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Ugawa
mesh_terms: D000328:Adult; D001931:Brain Mapping; D004558:Electric Stimulation; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*; D009068:Movement / Q000502:physiology; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology