THE CENTER MEDIAN AND PARAFASCICULAR THALAMIC NUCLEI PROJECT RESPECTIVELY TO THE SENSORIMOTOR AND ASSOCIATIVE LIMBIC STRIATAL TERRITORIES IN THE SQUIRREL-MONKEY

The striatal projections of the centre médian (CM) and parafascicular (Pf) thalamic nuclei were examined in the squirrel monkey (Saimiri sciureus) by using the lectin wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) as an anterograde tracer. CM was found to project massively to the putamen, where terminal fields appeared principally in the form of oblique bands, and more diffusely to the dorsolateral border of the caudate nucleus. Striatal inputs from Pf were found more rostrally, especially in the ventromedial portion of the putamen, the entire ventromedial half of the caudate nucleus, and the ventral striatum including the nucleus accumbens and the olfactory tubercle. Pf terminal fields in the rostral striatum often displayed a patchy organization. Both CM and Pf projections were found to terminate in the matrix compartment of the striatum as defined by acetylcholinesterase staining. These results suggest that CM is more specifically involved in sensorimotor and Pf in associative and limbic aspects of basal ganglia function in primates. © 1990.