Figure 16. Diagrammatic representation of sequential coronal views of the rat brain, illustrating the VIP chemistry of the suprachiasmatic nucleus. VIP neurons (blue) are seen to be localized to the SCN, with efferents projecting locally and posteriorly to the hypothalamus and thalamus. VIP binding (red) is shown, with the intensity of the color representing the density of VIP binding. The afferent connections of the SCN are shown in the insert, which was taken, with permission, from Bosler et al. (11). AH, anterior hypothalamic nucleus; AVP, vasopressin; DMH, dorsomedial hypothalamic nucleus; GRP, gastrin releasing peptide; 5-HT, serotonin; IGL, intergeniculate leaflet of the lateral geniculate nucleus of the thalamus; MPO, medial preoptic region; NAAG, N-acetylaspartyl glutamate; NPY, neuropeptide Y; PVN, paraventricular nucleus of the hypothalamus; PVP, paraventricular nucleus of the thalamus; SCN, suprachiasmatic nucleus; SRIF, somatostatin.