Ultrastructural differences between pallidohabenular terminals and pallidothalamic terminals.

Pallidal terminals in the cat lateral habenular nucleus and the ventral anterior and ventral lateral nuclear complex of the thalamus have been examined electron microscopically. A significant difference was obtained after a quantitative analysis of size and shape parameters of synaptic vesicles in the identified terminals: synaptic vesicles in the pallidohabenular terminals had smaller mean elongation index and larger mean vesicle profile area than those in the pallidothalamic terminals.