Epigenetics and Neurobiology Unit, European Molecular Biology Laboratory, 00015 Monterotondo (RM), Italy.
Neurobiology Master's Program, Sapienza University of Rome, 00185 Rome, Italy.
Proc Natl Acad Sci U S A. 2021 Apr 13;118(15). doi: 10.1073/pnas.2013411118.
Predators must frequently balance competing approach and defensive behaviors elicited by a moving and potentially dangerous prey. Several brain circuits supporting predation have recently been localized. However, the mechanisms by which these circuits balance the conflict between approach and defense responses remain unknown. Laboratory mice initially show alternating approach and defense responses toward cockroaches, a natural prey, but with repeated exposure become avid hunters. Here, we used in vivo neural activity recording and cell-type specific manipulations in hunting male mice to identify neurons in the lateral hypothalamus and periaqueductal gray that encode and control predatory approach and defense behaviors. We found a subset of GABAergic neurons in lateral hypothalamus that specifically encoded hunting behaviors and whose stimulation triggered predation but not feeding. This population projects to the periaqueductal gray, and stimulation of these projections promoted predation. Neurons in periaqueductal gray encoded both approach and defensive behaviors but only initially when the mouse showed high levels of fear of the prey. Our findings allow us to propose that GABAergic neurons in lateral hypothalamus facilitate predation in part by suppressing defensive responses to prey encoded in the periaqueductal gray. Our results reveal a neural circuit mechanism for controlling the balance between conflicting approach and defensive behaviors elicited by the same stimulus.
捕食者必须经常平衡由移动的和潜在危险的猎物引起的竞争接近和防御行为。最近已经定位了支持捕食的几个大脑回路。然而,这些回路如何平衡接近和防御反应之间的冲突的机制仍不清楚。实验室小鼠最初对蟑螂这种天然猎物表现出交替的接近和防御反应,但随着反复暴露,它们会变成贪婪的猎手。在这里,我们使用雄性猎食小鼠的体内神经活动记录和细胞类型特异性操作,鉴定了编码和控制捕食性接近和防御行为的外侧下丘脑和导水管周围灰质中的神经元。我们发现外侧下丘脑中的一组特定编码猎食行为的 GABA 能神经元,其刺激会引发捕食行为而不是进食。这群神经元投射到导水管周围灰质,刺激这些投射促进了捕食行为。导水管周围灰质中的神经元编码了接近和防御行为,但只有当老鼠对猎物表现出高度恐惧时才会出现这种行为。我们的发现使我们能够提出,外侧下丘脑中的 GABA 能神经元通过抑制导水管周围灰质中编码的对猎物的防御反应来促进捕食行为。我们的研究结果揭示了一种控制由同一刺激引起的冲突的接近和防御行为之间平衡的神经回路机制。