Demonstration of Bilateral Claustro-Cortical Connections in the Cat with the Method of Retrograde Axonal Transport of Horseradish Peroxidase

Abstract

The claustrum of the cat was studied to determine the extent of its projection to the cerebral cortex. Neurons in the bilateral dorsal claustrum were labeled by retrograde axonal transport of horseradish peroxidase (HRP) from injection sites of different neocortical areas with preponderance to the ipsilateral side. The dorsal claustrum projects to almost entire regions of the bilateral neocortex and the distribution of labeled neurons in the bilateral claustrum has topographical correspondence, rostro-caudal and dorso-ventral, with regard to the sites of injections in the neocortex. No neurons in the ventral claustrum were labeled.