SUBCORTICAL CONNECTIONS OF INFERIOR TEMPORAL AREAS TE AND TEO IN MACAQUE MONKEYS

To investigate the subcortical connections of inferior temporal cortex , we injected its anterior and posterior portions (Bonin and Bailey's cytoarchitectonic areas TE and TEO, respectively) in 6 rhesus monkeys with retrograde and anterograde tracers. The results indicate that bot h areas TE and TEO receive nonreciprocal inputs from several thalamic nuclei, including paracentralis, ventralis anterior, centralis, and li mitans, and that TE also receives input from reuniens. Additional nonr eciprocal inputs to both areas arise from the hypothalamus, basal nucl eus of Meynert, dorsal and median raphe, locus coeruleus, and reticula r formation. TE and TEO are reciprocally connected with the lateral, m edial, and inferior nuclei of the pulvinar and with the ventral portio n of the claustrum. The main subcortical nonreciprocal output from TE and TEO is to the striatum and from TEO to the superior colliculus. TE also sends a very limited projection to nucleus medialis dorsalis mag nocellularis of the thalamus. Although the connections of areas TE and TEO are overlapping in most subcortical structures, they are partiall y segregated in the pulvinar, the reticular nucleus of the thalamus, a nd the striatum. Specifically, relative to those of TE, the projection s of TEO are located more laterally in the medial, lateral, and inferi or nuclei of the pulvinar, more ventrally in the reticular nucleus, an d more caudally in both the ventral putamen and tail and head of the c audate nucleus. (C) 1993 Wiley-Liss, Inc.