A Golgi study on neuronal morphology of the ventral lateral geniculate nucleus of the lizard

The architecture and cellular morphology of the ventral geniculate nucleus (vLGN) of Lacerta sicula (Rafinesque) were investigated by means of classical neuroanatomical methods (Bodian, Klüver-Barrera, Cresyl-violet, and rapid Golgi impregnation). The vLGN of L. sicula is located in the laterodorsal portion of the diencephalon throughout the ventral thalamus. It appears sickle-shaped in cross section and contains a) a lateral neuropil, close to the marginal optic tract; b) a medial cell plate and c) an internal neuropil. Golgi preparations show a diffuse population of multipolar, "tufted" and bipolar neurons together with scattered glial cells in the lateral neuropil of vLGN. In the cell plate, two or three rows of cells of medium size, largely corresponding to the so called "cellule a doppio pennacchio" (Beccari, 1923) are found. These cells are endowed with two dendritic trunks, extending respectively into the internal neuropil and toward the optic tract. This latter process shows a quite complex arborization, closely intermingling with the retinal fibres arising from the marginal optic tract. The axons of these cells contribute to the fasciculus geniculatus descendens, the main efferent system of the vLGN.