title: Electron microscopic identification of reticulo-subthalamic axon terminals in the cat.
abstract: Synaptic boutons emanating from axons of nucleus tegmenti pedunculopontinus origin were identified by electron microscopy in the neuropil of the subthalamic nucleus. Such boutons measure 1.5-3 microns, contain round synaptic vesicles and make asymmetrical axodendritic and axosomatic synaptic contacts with large subthalamic neurons. Very few contacts with vesicle-containing dendrites, and no contacts with the perikarya of the small neurons were observed. The present findings, in keeping with the relevant light microscopic and electrophysiologic data, furnish evidence for a substantial bilateral tegmenti pedunculopontinofugal projection that excites monosynaptically the relay subthalamic neurons.
mesh_terms: D000818:Animals; D001369:Axons / Q000648:ultrastructure*; D002415:Cats; D008854:Microscopy, Electron; D009416:Nerve Regeneration; D011149:Pons / Q000502:physiology; D012154:Reticular Formation / Q000648:ultrastructure*; D013569:Synapses / Q000502:physiology; D013788:Thalamus / Q000648:ultrastructure*; D013997:Time Factors