FIGURE 8.

The three-dimensional distribution of MCH neurons in Muroids. Hypothalamic reconstructions from R. norvegicus (a), M. musculus (b), and N. alstoni (c). Each neuron is indicated by a magenta dot. Notable differences are observed when the three species are compared. The distribution of MCH neurons occupies virtually the whole medio-lateral extent of the tuberal hypothalamus, with neurons ranging from the ventricle border to the internal margin of the internal capsule. Only a small number of neurons is found ventral to the fornix. In contrast, the mouse periventricular nucleus and the medial part of the lateral hypothalamic area (LHA) are mostly devoid of neurons, with the anterior hypothalamic area and the dorsolateral LHA representing the largest groups. In N. alstoni, an intermediate profile is observed, with moderate numbers of neurons observed in the medial LHA and the periventricular area. The Mexican volcano mouse, however, distinguishes itself for a substantial presence of MCH neurons ventral to the fornix, in the perifornical area. Animated versions of these reconstructions can be found in Diniz et al. (2019). Structures: 3V, third ventricle (orange); f, fornix (yellow); ic, internal capsule (purple); mt, mammillothalamic tract (green); opt, optic tract (blue). Reproduced with permission from Diniz et al. (2019).