A retinoraphe projection regulates serotonergic activity and looming-evoked defensive behaviour

作者：Lu Huang, Tifei Yuan, Minjie Tan, Yue Xi, Yu Hu, Qian Tao, Zhikai Zhao, Jiajun Zheng, Yushui Han, Fuqiang Xu, Minmin Luo, Patricia J. Sollars, Mingliang Pu, Gary E. Pickard, Kwok‐Fai So, Chaoran Ren · 发表于：Nature Communications · 年份：2017 · DOI：10.1038/ncomms14908 · 被引用次数：102 · 研究领域：Receptor Mechanisms and Signaling、Neuroscience and Neuropharmacology Research、Retinal Development and Disorders

Animals promote their survival by avoiding rapidly approaching objects that indicate threats. In mice, looming-evoked defensive responses are triggered by the superior colliculus (SC) which receives direct retinal inputs. However, the specific neural circuits that begin in the retina and mediate this important behaviour remain unclear. Here we identify a subset of retinal ganglion cells (RGCs) that controls mouse looming-evoked defensive responses through axonal collaterals to the dorsal raphe nucleus (DRN) and SC. Looming signals transmitted by DRN-projecting RGCs activate DRN GABAergic neurons that in turn inhibit serotoninergic neurons. Moreover, activation of DRN serotoninergic neurons reduces looming-evoked defensive behaviours. Thus, a dedicated population of RGCs signals rapidly approaching visual threats and their input to the DRN controls a serotonergic self-gating mechanism that regulates innate defensive responses. Our study provides new insights into how the DRN and SC work in concert to extract and translate visual threats into defensive behavioural responses.