Direct projections from the globus pallidus to the paraventricular nucleus of the thalamus in the rat.

After injecting horseradish peroxidase into the thalamic regions around the paraventricular thalamic nucleus (Pv) in the rat, small neurons in the globus pallidus (GP) were labeled retrogradely with the enzyme. After injecting [3H]leucine into the GP, terminal labeling was autoradiographically observed in the Pv bilaterally with an ipsilateral dominance. These terminals in the Pv were shown by electron microscopic autoradiography to make asymmetrical synaptic contacts upon small dendrites of Pv neurons.