High-frequency SEP components generated in the somatosensory cortex of the monkey.
To investigate the origin of high-frequency somatosensory evoked potential (SEP) components, we recorded median nerve SEPs from the scalp and the depth in six monkeys. Laminar field potentials were analyzed in area 3b (N10; corresponding to human N20) and area 1 (P12; corresponding to human P25). After digital filtering (300-900 Hz), 4-6 components were identified, and the 1st to 4th peaks in area 3b (7-11 ms in latency) and the 3rd to 5th in area 1 (9-13 ms) showed clear polarity reversals between the surface and the depth of the cortex. These results provide direct evidence for intracortical origin of early high-frequency components in area 3b and of late ones in area 1.
Shimazu
H
H
Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto University Hospital, Japan.
Kaji
R
R
Tsujimoto
T
T
Kohara
N
N
Ikeda
A
A
Kimura
J
J
Shibasaki
H
H
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D008251:Macaca; D008475:Median Nerve / Q000502:physiology; D009991:Oscillometry; D011930:Reaction Time / Q000502:physiology; D012535:Scalp / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology*