Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, 1501 San Pablo Street, Los Angeles, CA, 90033, USA.
Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, 90089, USA.
Nat Commun. 2022 Mar 7;13(1):1194. doi: 10.1038/s41467-022-28854-z.
Valence detection and processing are essential for the survival of animals and their life quality in complex environments. Neural circuits underlying the transformation of external sensory signals into positive valence coding to generate appropriate behavioral responses remain not well-studied. Here, we report that somatostatin (SOM) subtype of GABAergic neurons in the mouse medial septum complex (MS), but not parvalbumin subtype or glutamatergic neurons, specifically encode reward signals and positive valence. Through an ascending pathway from the nucleus of solitary tract and then parabrachial nucleus, the MS SOM neurons receive rewarding taste signals and suppress the lateral habenula. They contribute essentially to appetitive associative learning via their projections to the lateral habenula: learning enhances their responses to reward-predictive sensory cues, and suppressing their responses to either conditioned or unconditioned stimulus impairs acquisition of reward learning. Thus, MS serves as a critical hub for transforming bottom-up sensory signals to mediate appetitive behaviors.
价态检测和处理对于动物在复杂环境中的生存和生活质量至关重要。将外部感觉信号转化为正价态编码以产生适当行为反应的神经回路仍未得到充分研究。在这里，我们报告说，小鼠中隔复合体（MS）中的生长抑素（SOM）亚型 GABA 能神经元，而不是副甲状腺素或谷氨酸能神经元，特异性地编码奖励信号和正价态。通过从孤束核到臂旁核的上行通路，MS SOM 神经元接收令人愉悦的味觉信号，并抑制外侧缰核。它们通过投射到外侧缰核对食欲联想学习做出重要贡献：学习增强了它们对奖励预测性感觉线索的反应，而抑制它们对条件或非条件刺激的反应则会损害奖励学习的获得。因此，MS 作为一个关键的枢纽，将从下到上的感觉信号转化为介导食欲行为。
