Neurons of the dorsal lateral geniculate nucleus of the albino rat

Abstract

Light and electron microscopic observations were made on the dorsal lateral geniculate nucleus (DLGN) of 33 young adult male albino rats. Three variants of the Golgi silver impregnation technique were employed in the light microscopic studies. Neurons were classified into three categories based on location, dendritic pattern, and dendritic appendages. Type 1 and type 3 neurons were distributed throughout the DLGN. Type 2 neurons were located in the superficial zone. Dendritic appendages of type 1 and type 2 neurons indicated these cells may function as geniculo-cortical relay neurons. The type 3 neurons had lobulated dendritic appendages and an axon that terminated withinthe nucleus. Type 3 neurons may represent Golgi-type-II interneurons. Camera lucida drawings, photomicrographs, and electronmicrographs illustrate the characteristics ofthe three cell types. The literature on ultrastructural and neurophysiological findings may substantiate the presence of three neuronal types. Initially, the rat DLGN does not appear as elaborately organized as the nucleus observed in cats and primates; however, there are notable similarities in neuronal morphology and synaptology.