A three-dimensional reconstruction of the rat hypothalamus

Tracings of structures present in serial coronal frozen sections of the rat hypothalamus were entered into an IBM-PC and sections were aligned in space using a program for 3-dimensional reconstruction. The positions and relative volumes of 16 major hypothalamic nuclei were accurately displayed in lateral, medial, and superior views of the hypothalamus. Three major clusters of hypothalamic nuclei were apparent, reinforcing embryological concepts of "neuromeres" from which adult structures develop. A better knowledge of the spatial locations of hypothalamic nuclei, which determine the pathways of intrahypothalamic connections, should be of aid in interpreting studies which disrupt such connections.