ナカムラ　カエ   NAKAMURA KAE   中村　加枝    所属   関西医科大学  生理学講座    職種   教授
言語種別	日本語
発表タイトル	価値に基づく意思決定の神経機構―新たな展開 Role of basal ganglia for reward-dependent modulation of action; New perspectives on value-based　decision making.
会議名	第33回　日本神経科学大会　Neuro2010
学会区分	全国規模の学会
発表形式	口頭
講演区分	特別講演・招待講演など
発表者・共同発表者	◎Nakamura, K.
発表年月日	2010/09
開催地 （都市, 国名）	神戸
概要	It has been hypothesized that the dorsal striatum (DS), once primarily studied in relation to motor function, is also a structure which controls selection of action to obtain rewards. The ventral striatum (VS), on the other hand, has long been studied in relation to reward and motivation. However, the specific nature of VS's contribution to the motivational behavior is unclear. To test whether different reward information is represented in primate DS and VS, we recorded from single neurons in DS and VS of the same monkeys performing asymmetrically rewarded visually-guided and memory-guided saccade tasks. In a given block, one of two target cue positions was associated with a large reward and the other with a small reward. The cue position - reward size association was switched every 16-20 trials. Neurons in the striatum exhibited task related activity during pre-cue, post-cue, saccade, and post-reward periods all of which was often modulated by some aspects of reward. We now found these neurons were inhomogeneous in distribution. Neurons showing differential modulation in activity during the pre-cue/movement periods depending on rewarded position, and phasic direction- or reward-dependent modulation in activity during the post-cue and/or peri-saccadic periods, were observed more commonly in DS than in VS. Conversely, neurons showing long-lasting (often >1sec) reward dependent modulation after reward delivery were more prevalent in VS than in DS. In VS, some neurons also exhibited enhancement in activity related to the initiation of the task, switch of the rewarded cue position, or commission of errors. Thus, we propose DS provides spatially relevant reward information which may be useful for executing routine trials while VS provides reward information which may be useful for updating general course of action. Such regional difference may also be related to dissimilar response pattern observed in dopamine and dorsal raphe neurons projecting to DS and VS.