The parageniculate nucleus in carnivores

Abstract

The present study attempts to study the comparative anatomy of the parageniculate nucleus in carnivores. In Felidae it is closely applied to the lateral margins of the posterior lateral and suprageniculate nuclei, and is composed of small, deeply stained and fusiform cells. Caudally it lies just lateral to the ventrolateral part of the lateral pulvinar nucleus and to the suprageniculate nucleus. As the dorsal lateral geniculate nucleus appears, the parageniculate nucleus extends ventrally between the dorsal lateral geniculate nucleus and the suprageniculate nucleus or the inferior pulvinar nucleus. In the other carnivores examined, the parageniculate nucleus tends to be confined to the lateral margins of the lateral pulvinar and suprageniculate nuclei. At the most anterior levels of the dorsal lateral geniculate nucleus, the parageniculate nucleus extends ventrolaterally to reach the region just dorsomedial to the dorsal lateral geniculate nucleus, but does not extend between the geniculate nucleus and the dorsal thalamus proper. The parageniculate nucleus is regarded as a connecting cell group between the dorsal lateral geniculate nucleus and the dorsal thalamus proper, and may be a dorsal thalamic derivative.