| Project/Area Number |
14380377
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Kyoto Prefectural University of Medicine |
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Principal Investigator |
KIMURA Minoru Kyoto Prefectural University of Medicine, Graduate School of Medicine, professor, 医学研究科, 教授 (40118451)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUMOTO Naoyuki Kyoto Prefectural University of Medicine, Graduate School of Medicine, Instructor, 医学研究科, 助手 (00252726)
UEDA Yasumasa Kyoto Prefectural University of Medicine, Graduate School of Medicine, Instructor, 医学研究科, 助手 (60332954)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥14,800,000 (Direct Cost: ¥14,800,000)
Fiscal Year 2004: ¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 2003: ¥5,400,000 (Direct Cost: ¥5,400,000)
Fiscal Year 2002: ¥5,500,000 (Direct Cost: ¥5,500,000)
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| Keywords | Basal Ganglia / Striatum / Dopamine Neurons / Motivation / Reward / Value / Aversion / Thalamo-striate system / 視床髄板内核 / 予測 / 注意 / 視庄髄板内核 |
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| Research Abstract |
We conducted the following two core projects supported by the grant for the three-year term from 2002 to 2004.
Project 1: Identification of neuronal information encoded by the midbrain dopamine neurons
We recorded activity of single midbrain dopamine neurons of monkeys performing decision-making and action selection task under different reward probabilities. We found that activity of dopamine neurons code both reward expectation error and motivation signals. The coding of reward expectation error will help modification of action and cognition signals in the target structures, the striatum limbic system and cerebral frontal cortex. On the other hand, coding of motivation will work as an incentive to work for a reward. This process will motivate subjects toward their goals. The motivation coding will be used to control the gain of coding reward expectation errors in such a way that larger amount of dopamine delivery to encode an error when subjects are motivated, while smaller amount of dopamine delivery when less motivated.
Project 2: Coding of motivation and value in the striatum
In order to understand representation of information in the striatum of action, contexts of reward and aversion and reward expectation, we recorded single neuron activity of the striatum of monkeys performing behavioral tasks. We found that, for the representation of action, striatal neurons code signals required for goal-directed assembling of action-related information, such as combination and sequence of movement rather than control parameters of movement, such as direction, velocity and size of movement. We found that striatal neurons detect and discriminate motivational contexts for an action, such as reward and aversion. We also found by functional imaging study of human brain that the striatum especially the caudate nucleus is involved in reward-based action selection learning.
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