Modulation of neuronal firing rates by the spatial locations of physical objects is a widespread phenomenon in the brain. However, little is known about how neuronal responses to the actions of biological entities are spatially tuned and whether such spatially tuned responses are affected by social contexts. These issues are of key importance for understanding the neural basis of embodied social cognition, such as imitation and perspective-taking. Here, we show that spatial representation of actions can be dynamically changed depending on others’ social relevance and agents of action. Monkeys performed a turn-taking choice task with a real monkey partner sitting face-to-face or a filmed partner in prerecorded videos. Three rectangular buttons (left, center, and right) were positioned in front of the subject and partner as their choice targets. We recorded from single neurons in two frontal nodes in the social brain, the ventral premotor cortex (PMv) and the medial prefrontal cortex (MPFC). When the partner was filmed rather than real, spatial preference for partner-actions was markedly diminished in MPFC, but not PMv, neurons. This social context-dependent modulation in the MPFC was also evident for self-actions. Strikingly, a subset of neurons in both areas switched their spatial preference between self-actions and partner-actions in a diametrically opposite manner. This observation suggests that these cortical areas are associated with coordinate transformation in ways consistent with an actor-centered perspective-taking coding scheme. The PMv may subserve such functions in context-independent manners, whereas the MPFC may do so primarily in social contexts.

中文翻译：

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猕猴额叶皮层自我和他人行为的动态空间表征


物理对象的空间位置对神经元放电率的调节是大脑中普遍存在的现象。然而，人们对神经元对生物实体行为的反应如何在空间上进行调整以及这种空间调整的反应是否受到社会环境的影响知之甚少。这些问题对于理解模仿和换位思考等具身社会认知的神经基础至关重要。在这里，我们表明，行为的空间表示可以根据他人的社会相关性和行为主体动态改变。猴子与面对面坐着的真正猴子伙伴或预先录制的视频中拍摄的伙伴一起执行轮流选择任务。三个矩形按钮（左、中、右）位于受试者和伙伴的前面，作为他们的选择目标。我们从社交脑中两个额叶节点的单个神经元进行记录，即腹侧前运动皮层（PMv）和内侧前额叶皮层（MPFC）。当伴侣被拍摄而不是真实时，MPFC 神经元对伴侣动作的空间偏好明显减弱，但 PMv 神经元却没有。 MPFC 中这种依赖于社会背景的调节对于自我行动也很明显。引人注目的是，这两个区域的一部分神经元以完全相反的方式在自我行为和伙伴行为之间切换空间偏好。这一观察结果表明，这些皮质区域与坐标变换相关，其方式与以行动者为中心的视角编码方案一致。 PMv 可以以与环境无关的方式促进这些功能，而 MPFC 可以主要在社交环境中这样做。