A different framework to classify preoptic and hypothalamic nuclei in reptiles

Abstract

The preoptic area and the hypothalamus are inextricably linked. Together, they represent an area of the forebrain that is essential for survival of the species. Observations in mammals have suggested a classification of these structures into four rostrocaudal areas and three mediolateral zones. Two species of crocodiles were investigated to determine if this scheme or a modification of it could be applied to these reptiles. The resulting classification identified three rostrocaudal areas based on their respective relationship to the ventricular system: preoptic, anterior, and tuberal and four mediolateral zones: ependyma, periventricular, medial, and lateral. This scheme avoided the cumbersome and complicated nomenclature that has traditionally been used for morphologic studies of these areas in other reptiles, including crocodiles. The present classification is simple, straightforward, and readily applicable to other reptiles.