Hypocretin System and Aminergic and Cholinergic Systems in the Control of Vigilance

The hypothalamus plays a central role in the maintenance of homeostasis by integrating central and peripheral signals and controlling behaviors like sleep and food intake. Neural pathways connecting different hypothalamic and brainstem nuclei, peripherally released hormones, receptors, and outputs from the hypothalamus constitute the anatomical substrate for this homeostatic regulation. It has long been known that the posterior hypothalamus acts as a waking center and that damage to this region causes profound increases in the time spent sleeping, whereas the anterior hypothalamus contains regions that promote sleep, and lesions in this region cause insomnia (1,2).