Hyoung F. Kim, and Okihide Hikosaka
Neuron in Press
適切な意思決定を行うためには、「モノや行動、選択肢の価値」を「A. 柔軟に更新」しつつ「B. 長期間保持」している必要がある。
Choosing valuable objects is critical for survival, but their values may change flexibly or remain stable. Therefore, animals should be able to update the object values flexibly by recent experiences and retain them stably by long-term experiences. However, it is unclear how the brain encodes the two conflicting forms of values and controls behavior accordingly. We found that distinct circuits of the primate caudate nucleus control behavior selectively in the flexible and stable value conditions. Single caudate neurons encoded the values of visual objects in a regionally distinct manner: flexible value coding in the caudate head and stable value coding in the caudate tail. Monkeys adapted in both conditions by looking at objects with higher values. Importantly, inactivation of each caudate subregion disrupted the high-low value discrimination selectively in the flexible or stable context. This parallel complementary mechanism enables animals to choose valuable objects in both flexible and stable conditions.