Substantia Nigra Output to Prefrontal Cortex Via Thalamus in Monkeys. I. Electrophysiological Identification of Thalamic Relay Neurons

1 Departments of Physiology and 2 Neurosurgery, Shiga University of Medical Science, Ohtsu, Japan Submitted 30 November 2008; accepted in final form 14 August 2009 ABSTRACT A few studies have been performed in primate basal ganglia–thalamo–prefrontal pathways. Nevertheless, their electrophysiological properties and anatomical arrangements remain obscure. This study examined them in nigro-thalamo-cortical pathways from the substantia nigra pars reticulata (SNr) to the frontal cortex (FRC) via the mediodorsal (MD) and ventral anterior (VA) thalamus in monkeys. First, single thalamocortical neurons with SNr input were identified by antidromic responses to FRC stimulation and by inhibitory orthodromic responses with short latencies (