The medial frontal cortex has been linked to voluntary action, but an explanation of why decisions to act emerge at particular points in time has been lacking. We show that, in macaques, decisions about whether and when to act are predicted by a set of features defining the animal's current and past context; for example, respectively, cues indicating the current average rate of reward and recent previous voluntary action decisions. We show that activity in two brain areas-the anterior cingulate cortex and basal forebrain-tracks these contextual factors and mediates their effects on behavior in distinct ways. We use focused transcranial ultrasound to selectively and effectively stimulate deep in the brain, even as deep as the basal forebrain, and demonstrate that alteration of activity in the two areas changes decisions about when to act.

中文翻译：

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猕猴的基底前脑-扣带回回路决定是时候采取行动了。

内侧额叶皮层与自愿行动有关，但一直缺乏对为何在特定时间点出现行动决定的解释。我们表明，在猕猴中，是否以及何时采取行动的决定是由一组定义动物当前和过去背景的特征来预测的；例如，分别表示当前平均奖励率和最近以前的自愿行动决定的线索。我们展示了两个大脑区域的活动——前扣带皮层和基底前脑——跟踪这些背景因素并以不同的方式调节它们对行为的影响。我们使用聚焦经颅超声来选择性和有效地刺激大脑深处，甚至与基底前脑一样深，并证明这两个区域的活动改变会改变关于何时采取行动的决定。