Three-dimensional structure of the mammalian suprachiasmatic nuclei: a comparative study of five species.

The suprachiasmatic nuclei from five mammalian species (rat, hamster, cat, rhesus, and squirrel monkey) were reconstructed in three-dimensions by use of computer graphics and conventional histological techniques. The gross nuclear structures of the suprachiasmatic nuclei have complex three-dimensional geometries in every plane of orientation, and between the five species there are marked differences in the three-dimensional morphology of the suprachiasmatic nuclei. These dimensionally accurate reconstructions are discussed in relation to previous data suggesting morphological and/or functional specialization within specific regions of the suprachiasmatic nuclei.