Recurrent neural networks (RNNs) are designed to learn sequential patterns in silico, but it is unclear whether and how an RNN forms in the native networks of the mammalian brain. Here, we report an innate RNN, which is formed by the unidirectional connections from three basic units: input units arriving from emotion regions, a hidden unit in the medial prefrontal cortex (mPFC), and output units located at the somatic motor cortex (sMO). Specifically, the neurons from basal lateral amygdala (BLA) and the insular cortex (IC) project to the mPFC motor-cortex-projecting (MP) neurons. These MP neurons form a local self-feedback loop and target major projecting neurons of the sMO. Within the sMO, the neurons in the infragranular layers receive stronger input than the neurons in supragranular layers. Finally, we show in vivo evidence that the communications from the emotion regions to the sMO are abolished when MP neurons are chemogenetically silenced.

循环神经网络 (RNN) 旨在通过计算机模拟学习顺序模式，但目前尚不清楚 RNN 是否以及如何在哺乳动物大脑的本地网络中形成。在这里，我们报告了一个先天 RNN，它由三个基本单元的单向连接形成：来自情感区域的输入单元、内侧前额叶皮层 (mPFC) 中的隐藏单元和位于体细胞运动皮层 (sMO) 的输出单元。 ）。具体来说，来自基底外侧杏仁核 (BLA) 和岛叶皮质 (IC) 的神经元投射到 mPFC 运动皮质投射 (MP) 神经元。这些 MP 神经元形成局部自反馈回路并针对 sMO 的主要投射神经元。在 sMO 内，颗粒下层的神经元比颗粒上层的神经元接收更强的输入。最后，我们展示了体内证据，表明当 MP 神经元被化学遗传学沉默时，从情绪区域到 sMO 的通讯就会被消除。