| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1989: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1988: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
1) Set-related activity in the premotor cortex (PM) and supplementary motor area (SMA) of Japanese monkeys (Macaca fuscata) was classified into three categories: (1) activity selectively responding to the direction IS, (2) activity selectively responding to the amplitude IS, and (3) activity most apparent after both IS were presented, reflecting both direction and amplitude. Among neurons with set-related activity recorded in PM and SMA, neurons with the third pattern constituted the vast majority. Those observations support the hypothesis that PM and SMA set-related activity contributes to the preparation of the forthcoming movements by providing integrated movement parameters which can be utilized in lower motor centers.
2) The corticocortical input-output organization of PM and SMA was studied by either horseradish peroxidase (HRP) or wheat germ agglutinin conjugated HRP (WGA-HRP) injection in monkeys. When HRP was injected in MI, the HRP labeled neurons were found especially in PM immediately lateral to the superior precentral sulcus (SPS) where neurons with set-related activity were densely located. Thus, it was suggested that motor program as set-related activity in PM is transmitted to MI considered as a final common pathway of motor command from cerebral cortex. HRP labeled neurons were also found in SMA, postarcuate cortex, cingulate cortex, and area 5. When WGA-HRP was injected in the cortex immediately lateral to SPS, the labeled neurons were found in restricted regions of SMA, MI, cingulate cortex, and area 5. In contrast, when WGA-HRP was injected in the postarcuate cortex, labeled neurons were found in SMA, MI, cingulate cortex, area 5, and area 7b. Thus, considering the location of set-related neurons and different input-output organizations within PM, it was speculated that PM can be divided into at least two parts, one in the region around SPS and the other in the postarcuate cortex.
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