Hypothalamic CRH neurons orchestrate complex behaviours after stress

All organisms possess innate behavioural and physiological programmes that ensure survival. In order to have maximum adaptive benefit, these programmes must be sufficiently flexible to account for changes in the environment. Here we show that hypothalamic CRH neurons orchestrate an environmentally flexible repertoire of behaviours that emerge after acute stress in mice. Optical silencing of CRH neurons disrupts the organization of individual behaviours after acute stress. These behavioural patterns shift according to the environment after stress, but this environmental sensitivity is blunted by activation of PVN CRH neurons. These findings provide evidence that PVN CRH cells are part of a previously unexplored circuit that matches precise behavioural patterns to environmental context following stress. Overactivity in this network in the absence of stress may contribute to environmental ambivalence, resulting in context-inappropriate behavioural strategies. Animals exhibit a number of complex behaviours following stressful events, although the underlying circuitry is undetermined. Here, the authors use optogenetic targeting to identify a role for corticotrophin releasing hormone cells in the paraventricular nucleus in regulating such behavioural responses to acute stress.