2013年7月12日金曜日

Reduced Striatal Responses to Reward Prediction Errors in Older Compared with Younger Adults

Ben Eppinger, Nicolas W. Schuck, Leigh E. Nystrom, and Jonathan D. Cohen
J. Neurosci. 2013;33 9905-9912
http://www.jneurosci.org/cgi/content/abstract/33/24/9905?etoc

ヒトfMRI。
年配者は若者に比べ、報酬を手掛かりにした学習がうまくできない(損失を手掛かりにした学習に関しては差がない)。
また、報酬予測誤差に対する線条体(Striatum)の反応も鈍い。

We examined whether older adults differ from younger adults in how they learn from rewarding and aversive outcomes. Human participants were asked to either learn to choose actions that lead to monetary reward or learn to avoid actions that lead to monetary losses. To examine age differences in the neurophysiological mechanisms of learning, we applied a combination of computational modeling and fMRI. Behavioral results showed age-related impairments in learning from reward but not in learning from monetary losses. Consistent with these results, we observed age-related reductions in BOLD activity during learning from reward in the ventromedial PFC. Furthermore, the model-based fMRI analysis revealed a reduced responsivity of the ventral striatum to reward prediction errors during learning in older than younger adults. This age-related reduction in striatal sensitivity to reward prediction errors may result from a decline in phasic dopaminergic learning signals in the elderly.

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