Laboratory of Behavioral Neuroscience, Institute for Quantitative Biosciences (IQB), The University of Tokyo, Tokyo, Japan.
Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
Nat Commun. 2023 Jul 3;14(1):3458. doi: 10.1038/s41467-023-39081-5.
Perception of fear induced by others in danger elicits complex vicarious fear responses and behavioral outputs. In rodents, observing a conspecific receive aversive stimuli leads to escape and freezing behavior. It remains unclear how these behavioral self-states in response to others in fear are neurophysiologically represented. Here, we assess such representations in the ventromedial prefrontal cortex (vmPFC), an essential site for empathy, in an observational fear (OF) paradigm in male mice. We classify the observer mouse's stereotypic behaviors during OF using a machine-learning approach. Optogenetic inhibition of the vmPFC specifically disrupts OF-induced escape behavior. In vivo Ca imaging reveals that vmPFC neural populations represent intermingled information of other- and self-states. Distinct subpopulations are activated and suppressed by others' fear responses, simultaneously representing self-freezing states. This mixed selectivity requires inputs from the anterior cingulate cortex and the basolateral amygdala to regulate OF-induced escape behavior.
他人处于危险中所引起的恐惧感知会引发复杂的替代性恐惧反应和行为输出。在啮齿动物中，观察到同类接受厌恶刺激会导致逃避和冻结行为。目前尚不清楚这些针对他人恐惧的行为自我状态在神经生理学上是如何表现的。在这里，我们在雄性小鼠的观察性恐惧（OF）范式中评估了腹内侧前额叶皮层（vmPFC）中的这种表现，vmPFC 是同理心的一个重要部位。我们使用机器学习方法对 OF 期间观察鼠的刻板行为进行分类。光遗传学抑制 vmPFC 特异性地破坏了 OF 诱导的逃避行为。在体 Ca2+成像揭示 vmPFC 神经元群体同时代表了其他状态和自我状态的混杂信息。不同的亚群被他人的恐惧反应激活和抑制，同时代表自我冻结状态。这种混合选择性需要来自扣带前皮质和基底外侧杏仁核的输入来调节 OF 诱导的逃避行为。
