The temporal profile of interactions between sensory information from both hands in the secondary somatosensory cortex.
OBJECTIVE
To elucidate the temporal profile of interactions between sensory information from both hands in the somatosensory cortex.


METHODS
Somatosensory evoked fields (SEFs), generated by stimulation applied to the right index finger after a preceding stimulation to the left index finger, were recorded using a whole head-type magnetoencephalography (MEG). The paired electrical stimuli were applied with a stimulation onset asynchrony (SOA) of 50, 100, 200, 300, or 400 ms.


RESULTS
The mean SEF intensities in the primary somatosensory area (SI) of five subjects, which were evoked approximately 40 ms after the latter of the paired stimuli, were not significantly smaller than that evoked in the control condition when only the right finger was stimulated. In contrast, SEFs in the secondary somatosensory area (SII), generated approximately 100 ms after the stimuli, were suppressed when the paired stimuli were applied at an SOA of 100 ms (P<0.05, t test). In addition, SEFs at approximately 150 ms after the stimuli were significantly suppressed at SOAs of 50, 100 (P<0.05), 200, and 300 ms (P<0.1).


CONCLUSIONS
Within a time window of approximately 300 ms, sensory information from the left finger significantly affected the SEFs generated by sensory inputs from the right finger. This time window may be required for the integration of sensory input.
Hamada
Y
Y
Human Information System Laboratories, Kanazawa Institute of Technology, Matto, Ishikawa 924-0838, Japan. yhamada@mit.edu
Kado
H
H
Suzuki
R
R
D000328:Adult; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005385:Fingers / Q000294:innervation / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006225:Hand / Q000294:innervation* / Q000502:physiology*; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D013003:Somatosensory Cortex / Q000502:physiology*; D013997:Time Factors; D014110:Touch / Q000502:physiology*