Population coding of predator imminence in the hypothalamus.

UNLABELLED

Hypothalamic VMHdm neurons are activated by predator cues and are necessary and sufficient for instinctive defensive responses. However, such data do not distinguish which features of a predator encounter are encoded by VMHdm neural activity. To address this issue, we imaged VMHdm neurons at single-cell resolution in freely behaving mice exposed to a natural predator in varying contexts. Our results reveal that VMHdm neurons do not represent different defensive behaviors, but rather encode predator identity and multiple predator-evoked internal states, including threat-evoked fear/anxiety; neophobia or arousal; predator imminence; and safety. Notably, threat and safety are encoded bi-directionally by anti-correlated subpopulations. Finally, individual differences in predator defensiveness are correlated with differences in VMHdm response dynamics. Thus, different threat-related internal state variables are encoded by distinct neuronal subpopulations within a genetically defined, anatomically restricted hypothalamic cell class.

HIGHLIGHTS

Distinct subsets of VMHdm neurons encode multiple predator-evoked internal states. Anti-correlated subsets encode safety vs. threat in a bi-directional mannerA population code for predator imminence is identified using a novel assay VMHdm dynamics correlate with individual variation in predator defensiveness.