CALBINDIN-CONTAINING NONSPECIFIC THALAMOCORTICAL PROJECTING NEURONS IN THE RAT

Immunoreactivity for calcium binding proteins was used to demonstrate the neurochemical profiles of non-specific thalamocortical neurons loc ated in the ventromedial nucleus, the centrolateral nucleus, and the n ucleus reuniens that project to the somatosensory cortex in the adult rat. Cortical injections of fluorescent tracers combined with immunohi stochemistry for calcium binding proteins revealed that retrogradely l abeled neurons ih these three thalamic nuclei are immunoreactive for c albindin. The present results suggest the presence of a chemically dis tinct non-specific thalamocortical system which terminates in the neoc ortex.