Afferent and Efferent Connections of Temporal Association Cortex in the Rat: A Horseradish Peroxidase Study.

We studied the afferent and efferent connections of the caudal temporal cortex in rat using the tracer wheat germ agglutinin - horseradish peroxidase (WGA - HRP). This area is reciprocally connected with primary and secondary visual and auditory areas of cortex. The connections with primary visual cortex are restricted to the ventral and caudal parts of the caudal temporal area. Caudal temporal cortex has reciprocal connections with the perirhinal cortex and projects to the caudate - putamen and lateral and basolateral nuclei of the amygdala. It also has reciprocal connections with the nucleus lateralis posterior, the dorsal and medial divisions of the medial geniculate nucleus and the caudal part of the posterior nucleus of the thalamus. It projects to the deep layers of the superior colliculus, the pericentral nucleus of the inferior colliculus and to the ventral nucleus of the basilar pons. Our results suggest that the rat caudal temporal cortex forms part of a pathway that connects visual and auditory cortex with the limbic system, by the way of the amygdala and perirhinal cortex.