title: Intraoperative intrinsic optical imaging of neuronal activity from subdivisions of the human primary somatosensory cortex.
abstract: We performed intrinsic optical imaging of neuronal activity induced by peripheral stimulation from the human primary somatosensory cortex during brain tumor surgery for 11 patients. After craniotomy and dura reflection, the cortical surface was illuminated with a xenon light through an operating microscope. The reflected light passed through a bandpass filter, and we acquired functional images using an intrinsic optical imaging system. Electrical stimulation of the median nerve, or the first and fifth digits, induced biphasic intrinsic optical signals which consisted of a decrease in light reflectance followed by an increase. The decrease in light reflectance was imaged, and we identified a neural response area within the crown of the postcentral gyrus. In experiments on first and fifth digit stimulation, we identified optical responses in separated areas within the crown of the postcentral gyrus, i.e. near the central sulcus and near the postcentral sulcus. In the former response area, separate representations of the two fingers were observed, whereas in the latter response area, the two fingers were represented in the same region. A similar somatotopic representation was observed with electrical stimulation of the first and third branches of the trigeminal nerve. These results seem to support the hypothesis of hierarchical organization in the human primary somatosensory cortex.
authors.affiliation: Department of Physiology, Tokyo Medical and Dental University Graduate School and Faculty of Medicine, Tokyo 113-8519, Japan. katsushige.phy2@tmd.ac.jp
authors.forename: Katsushige
authors.initials: K
authors.lastname: Sato
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nariai
authors.forename: Shinichi
authors.initials: S
authors.lastname: Sasaki
authors.forename: Itaru
authors.initials: I
authors.lastname: Yazawa
authors.forename: Hiraku
authors.initials: H
authors.lastname: Mochida
authors.forename: Naohisa
authors.initials: N
authors.lastname: Miyakawa
authors.forename: Yoko
authors.initials: Y
authors.lastname: Momose-Sato
authors.forename: Kohtaro
authors.initials: K
authors.lastname: Kamino
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Ohta
authors.forename: Kimiyoshi
authors.initials: K
authors.lastname: Hirakawa
authors.forename: Kikuo
authors.initials: K
authors.lastname: Ohno
mesh_terms: D000328:Adult; D000368:Aged; D001931:Brain Mapping; D001932:Brain Neoplasms / Q000601:surgery*; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D005385:Fingers / Q000294:innervation; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000166:cytology / Q000502:physiology; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D009434:Neural Pathways; D009474:Neurons / Q000502:physiology*; D055095:Optics and Photonics / Q000295:instrumentation; D013003:Somatosensory Cortex / Q000166:cytology / Q000502:physiology*; D014276:Trigeminal Nerve / Q000166:cytology / Q000502:physiology*