The ventral striatopallidothalamic projection. III. Striatal cells of the olfactory tubercle establish direct synaptic contact with ventral pallidal cells projecting to mediodorsal thalamus.

After injection of HRP in the thalamic mediodorsal nucleus (MD) of the rat on one side followed by a superficial laminar heat lesion of the olfactory tubercle (Tu) on the same side, electron microscopic examination of DAB-reacted sections through the Tu revealed degenerating terminals contacting HRP-labeled neurons, confirming that a monosynaptic, two-neuron link extends, via a relay in ventral pallidum, between the superficial dense cell layer of the Tu and the MD.