A retinoraphe projection regulates serotonergic activity and looming-evoked defensive behaviour.
A retinoraphe projection regulates serotonergic activity and looming-evoked defensive behaviour.
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视网膜投射调节血清素能活动和迫在眉睫的防御行为
DOI：
10.1038/ncomms14908
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发表时间：
2017-03-31
影响因子：
16.6
通讯作者：
Ren C
中科院分区：
文献类型：
--
作者：
Huang L;Yuan T;Tan M;Xi Y;Hu Y;Tao Q;Zhao Z;Zheng J;Han Y;Xu F;Luo M;Sollars PJ;Pu M;Pickard GE;So KF;Ren C
动物通过躲避快速靠近且预示着威胁的物体来促进自身生存。在小鼠中，由上丘（SC）触发对逼近物体产生的防御反应，上丘会接收来自视网膜的直接输入。然而，始于视网膜并介导这一重要行为的特定神经回路仍不明确。在此，我们识别出一类视网膜神经节细胞（RGCs），它们通过轴突侧支与中缝背核（DRN）和上丘相连，从而控制小鼠对逼近物体产生的防御反应。由投射至中缝背核的视网膜神经节细胞传递的逼近信号，会激活中缝背核中的γ-氨基丁酸（GABA）能神经元，进而抑制5-羟色胺能神经元。此外，激活中缝背核中的5-羟色胺能神经元会减少对逼近物体产生的防御行为。因此，特定的一类视网膜神经节细胞能够对快速靠近的视觉威胁发出信号，它们向中缝背核的输入控制着一种5-羟色胺自我调节机制，该机制可调节先天性防御反应。我们的研究为中缝背核和上丘如何协同工作，将视觉威胁提取并转化为防御行为反应提供了新的见解。
目前，人们对先天性恐惧背后的神经回路仅有部分了解。黄等人识别出一类同时投射至中缝背核和上丘的视网膜神经节细胞，并表明这些视网膜神经节细胞介导了小鼠对逼近物体产生的防御行为。
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. Neural circuits underlying innate fear are only partially understood. Huang et al. identify a subset of retinal ganglion cells that project to both the dorsal raphe nucleus and the superior colliculus, and show that these RGCs mediate looming-evoked defensive behaviours in mice.