Convergence of afferent fibers from the entopeduncular nucleus and the substantia nigra pars reticulata onto single neurons in the ventromedial thalamic nucleus: an electron microscope study in the cat.

Convergence of afferent fibers from the entopeduncular nucleus (EP) and the substantia nigra pars reticulata (SNr) onto single neurons in the ventromedial thalamic nucleus (VM) was shown electron microscopically in the cat. Axon terminals from the EP were anterogradely labeled with wheat germ agglutinin-horseradish peroxidase (WGA-HRP) injected into the EP. Axon terminals from the SNr were degenerated by injecting ibotenic acid into the SNr. Both WGA-HRP-labeled axon terminals and degenerating ones were found on single neuronal profiles in the VM.