The morphology of the dorsal lateral geniculate nucleus: a Golgi and electron microscopic study

Abstract

In this study the dorsal nucleus of the lateral geniculate body (LGN) of the normal cat was examined using both light and electron microscopy. The study of the light microscopic structure of the nucleus and related structures was initiated using both Nissl and myelin-staining methods. A reconstruction model of the LGN was made from serial sections along several planes. The cell population of each of the cell layers and of the intervening fiber plexii of the nucleus were examined in detail. With the use of Golgi methods, which completely stain isolated nerve cells, it was possible to distinguish four different cell types. The structural characteristics of each of these cell types have been described and com-pared to the cell classifications previously proposed for the cat LGN, as well as the LGN of the monkey and the rat. At the ultrastructural level, the neuronal processes present within the nucleus appear sometimes arranged in complex aggregates which were described by Szentagothai (68, 69) as "synaptic glomerulii". In the course of the present work the neuronal profiles composing these synaptic glomerulii were studied in the normal cat. These observations have been compared with those reported by previous authors, in particular with those based on degeneration studies.