Non-cholinergic globus pallidus cells that project to the cortex but not to the subthalamic nucleus in rat.

A substantial population of small globus pallidus neurons was demonstrated to have axonal projections to the cerebral cortex using fluorescent retrograde transport techniques. This population was separate from the more numerous population of medium size globus pallidus cells projecting to the subthalamic nucleus and was also separate from the pallidal and especially peripallidal population of large cholinergic cells projecting to the cortex. Some of the small, non-cholinergic cells projecting to the cortex also gave off axonal collaterals to the paraventricular thalamic nucleus.