2003 Fiscal Year Final Research Report Summary
Coordinate frames for neuronal activities in the supplementary motor area, the premotor area and the primary motor cortex.
| Project/Area Number |
14580784
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
神経・脳内生理学
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| Research Institution | Tohoku University |
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Principal Investigator |
KAKEI Shinji Tohoku University, Graduate School of Life Sciences, Associate Prof., 大学院・生命科学研究科, 助教授 (40224365)
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| Project Period (FY) |
2002 – 2003
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| Keywords | the supplementary motor area / the premotor area / the primary motor cortex / coodinate transformation / monkye / neuron redording / coordinate system |
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| Research Abstract |
We recorded the activity of neurons in primary motor cortex (Ml) and ventral premotor cortex (PMv) in a monkey trained to perform a task which dissociates three major coordinate frames of wrist movement: muscle, wrist joint, and an extrinsic coordinate frame. We found three major types of neurons in Ml and PMv. The first type was termed "extrinsic-like." The activity of these neurons appeared to encode the direction of movement in space independent of the patterns of wrist muscle activity or joint movement that produced the movements. The second type was termed "extrinsic-like with gain modulation". The activity of these neurons appeared to encode the direction of movement in space, but the magnitude (gain) of neuronal activity depended on the posture of the forearm. The third type was termed "muscle-like" since their activity co-varied with muscle activity. The great majority of the directionally-tuned neurons in the PMv were classified as "extrinsic-like" (48/59, 81 %). A smaller group was classified as "extrinsic-like with gain modulation" (7/59, 12%). In Ml, the three types of neurons were more equally represented. Our results raise the possibility that cortical processing between Ml and PMv may contribute to a sensorimotor transformation between extrinsic and intrinsic coordinate frames. Recent modeling studies have demonstrated the computational plausibility of such a process.
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