The paraventricular nucleus of the hypothalamus: a key node in the control of behavioural states

The paraventricular nucleus (PVN) of the hypothalamus contains diverse populations of neuropeptide-producing neurons. These include neurons that synthesise oxytocin, vasopressin, corticotropin-releasing hormone, thyrotropin-releasing hormone and somatostatin. While it is well established that these neurons control the secretion of neuroendocrine hormones, there is growing evidence that they also control the expression of important homeostatic behaviours. Here we review recent data showing a critical role of PVN neurons in controlling arousal, social behaviour, defensive behaviour and pain. Collectively, this suggests that the PVN is a key node in a wider neural network controlling behavioural states.