Fig. 2.

Schematic anatomy of the hypothalamus and its functional connections with Locus Coeruleus. In panel a, the hypothalamic nuclei are represented along the anteroposterior axis, divided into four regions: preoptic, suprachiasmatic, median and tuberomammillary area. Nuclei are colored on the basis of their main function considered in the present paper: yellow for endocrine nuclei, green for autonomic ones, light blue for sleep/wake cycle regulators. In panel b are represented schematically the functional connections between the Locus Coeruleus (LC) and hypothalamus. At the center of the diagram there is the Locus Coeruleus, surrounded by three concentric circles; the inner one (green line) represents the autonomic part of paraventricular nucleus, the second one (yellow line) endocrine nuclei, while the outer one (blue line) represents the sleep/wake cycle regulator nuclei. The arrows exemplify the functional connections existing between LC and each hypothalamic nuclei; moreover, also the pericoerulear zone (PeriLC) is reported, to better represent the REM sleep network. DMN dorsomedial nucleus, MPO medial preoptic area, LC Locus Coeruleus, LC-NA Locus Coeruleus noradrenergic system, LHA lateral hypothalamic area, LPO lateral preoptic area, PeriLC pericoerulear zone, PVN paraventricular nucleus, SCN suprachiasmatic nucleus, SON supraoptic nucleus, TMN tuberomammillary nucleus