title: An event-related optical topography study of cortical activation induced by single-pulse transcranial magnetic stimulation.
abstract: To visualize cortical activations during transcranial magnetic stimulation (TMS), it is necessary to measure those activations at high spatiotemporal resolution while preventing interference with the magnetic property of a coil. One suitable method that satisfies these demands is optical topography (OT), which has been used in cortical activation studies. In the present study, single-pulse TMS was applied to the left primary motor area, and cortical responses at the stimulation site were measured simultaneously with event-related OT. When TMS was applied at 110% motor threshold (MT), we observed significant oxyhemoglobin increases that were both time-locked and correlated with the hemodynamic basis function. Moreover, when TMS was applied at 90% MT, significant oxyhemoglobin increases were detected even though there were no motor-evoked potentials. These results demonstrate that OT can directly measure cortical responses to subthreshold single-pulse TMS, independent of the afferent feedback from the peripheral neuromuscular activity.
authors.affiliation: Department of Cognitive and Behavioral Science, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Japan.
authors.forename: Yasuki
authors.initials: Y
authors.lastname: Noguchi
authors.forename: Eiju
authors.initials: E
authors.lastname: Watanabe
authors.forename: Kuniyoshi L
authors.initials: KL
authors.lastname: Sakai
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002560:Cerebrovascular Circulation; D004558:Electric Stimulation; D019054:Evoked Potentials, Motor; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*; D055095:Optics and Photonics; D010108:Oxyhemoglobins / Q000032:analysis; D019265:Spectroscopy, Near-Infrared; D050781:Transcranial Magnetic Stimulation
chemical_list: D010108:Oxyhemoglobins