Septohabenular connections in the rat, cat and monkey

Septohabenular projections were studied using the Nauta‐gygax method of staining degenerating axons. The results are in general agreement with those reported by others. However, the septum projects differentially to the habenula and the patterns differ slightly in the three species studied. Rostral parts of the septum projected to the lateral habenular nucleus and posterior parts to the medial nucleus. Dorsal and ventral structures of the septum had a slight dorsal ventral topography of projection in the stria medullaris thalami. Projection through the stria medullaris was confined to its medial part only in the rat. The largest number of fibers to bypass the habenula and terminate in the mesencephalic central gray occurred in the monkey.