Subregions of human MT complex revealed by comparative MEG and direct electrocorticographic recordings

R. Matsumoto, A. Ikeda, T. Nagamine, M. Matsuhashi, S. Ohara, J. Yamamoto, K. Toma, N. Mikuni, J. Takahashi, S. Miyamoto, H. Fukuyama, H. Shibasaki

Research output: Contribution to journalArticlepeer-review

Abstract

Objective: To locate the visual motion complex (MT+) and study its response properties in an epilepsy surgery patient. Methods: A 17-year-old epilepsy patient underwent invasive monitoring with subdural electrodes in the right temporo-parieto-occipital area. MT+ was investigated by cortical electric stimulation and by epicortical visual evoked potentials time-locked to motion onset of sinusoidal gratings (motion VEP). Motion-related visual evoked magnetic field (motion VEF) was also recorded before the electrode implantation to complement the invasive recording. Results: Motion VEPs revealed two subregions within MT+, generating early and late potentials respectively. The early activity with a peak around 130 ms was localized at a single electrode situated immediately caudal to the initial portion of the ascending limb of the superior temporal sulcus (AL-STS). The late activity, peaking at 242-274 ms, was located ventro-rostrally over three electrodes. Among the four electrodes with motion VEPs, cortical stimulation at the most caudal pair elicited motion-in-depth perception involving the whole visual field. In addition to two subregions revealed on the gyral crown, magnetoencephalography (MEG) demonstrated another subregion with a late motion VEF in AL-STS immediately rostral to the electrode with the early motion VEP. Conclusions: In combination with MEG recording, the present invasive exploration demonstrated human MT+ in a focal area of the temporo-parieto-occipital junction and delineated possible three subregions as indicated by the different latencies and distributions of the motion VEP/VEFs. Significance: Comparative MEG and direct electrocorticographic recordings delineated possible subregions within the human MT complex.

Original languageEnglish (US)
Pages (from-to)2056-2065
Number of pages10
JournalClinical Neurophysiology
Volume115
Issue number9
DOIs
StatePublished - Sep 2004
Externally publishedYes

Keywords

  • Cortical electric stimulation
  • Magnetoencephalography
  • Motion perception
  • MT/V5
  • Subdural electrode
  • Visual evoked potential

ASJC Scopus subject areas

  • Clinical Neurology
  • Radiology Nuclear Medicine and imaging
  • Neurology
  • Sensory Systems
  • Physiology (medical)

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