Figure 2.

The neuronal connections between circadian, sleep, and feeding centers within the hypothalamus.

Notes: The efferent projections from suprachiasmatic nucleus (SCN) target the dorsal subparaventricular zone (dSPZ) and ventral subparaventricular zone (vSPZ) with a subset of the axons extending to the dorsomedial nucleus (DMH) in the hypothalamus. Few direct axonal inputs from SCN and ventral SPZ to the sleep-regulating area of ventrolateral preoptic area (VLPO), and a larger contingent of the axons project to the dorsomedial hypothalamus (DMH). The DMH also receives inputs from the arcuate nucleus, which is recognized for regulating food intake and energy expenditure (EE) and sends projections to ventromedial hypothalamus (VMH). The DMH sends divergent afferents to i) sleep regulation center VLPO, ii) paraventricular nucleus (PVN) containing the neurons synthesizing corticotropin-releasing hormone and neurons that mediate preganglionic output to autonomous nervous system, and iii) lateral hypothalamus (LH), an area that contains the hunger-stimulating and wakefulness-promoting peptides.