2026-07-30 東京大学

「音から報酬を期待するマーモセット」の脳内で起こる、脳領域間での情報のやりとり
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霊長類の前頭頭頂ネットワークに影響を与える報酬期待シグナルの潜在的な貯蔵庫としての内側運動前野 Medial premotor cortex as a potential reservoir of reward expectancy signals influencing the primate frontoparietal network
Keisuke Sehara,Masashi Kondo,Yuka Hirayama,Teppei Ebina,Masafumi Takaji,Akiya Watakabe,Ken-ichi Inoue,Masahiko Takada,Tetsuo Yamamori & Masanori Matsuzaki
Communications Biology Published:30 July 2026
DOI:https://doi.org/10.1038/s42003-026-10672-4
Abstract
Reward expectancy plays an important role in modulating cortical activity associated with motivation, selection, and preparation of subsequent goal-directed movements. However, it is unclear how it is represented in the primate frontoparietal cortex in a form that is separable from activity for motor execution. Here, using common marmosets performing a classical conditioning task with auditory cues, we conducted wide-field one-photon calcium imaging of frontoparietal and auditory cortices while recording orofacial and body movements. Reward expectancy that was separable from licking, eye movement, and hand movement was represented in the medial part of the dorsorostral premotor cortex (mPMdr), but not the central part. Granger causality analysis revealed information flows from mPMdr to widespread frontoparietal areas beyond its functional subnetwork, specifically during the delay period before reward delivery. Our results suggest that in non-human primates, mPMdr serves to retain reward expectancy to modulate the frontoparietal network for subsequent movements.

