Comparative volumetric studies of the lateral geniculate body of mammals

Volumetric investigations of the dorsal and ventral nucleus of the lateral geniculate body (dLGN and vLGN) in 16 mammalian species showed that forms with a high level of neocorticalization are characterized by a high quotient of dLGN and vLGN volumina. This result may be explained by the very different fibre connections of these two nuclei and the close relationship of the dLGN to the visual cortex. Compared with terrestric forms of the same body size tree living forms belonging to the same mammalian order have a larger LGN. The dLGN of these arboreal species exhibits additionally a higher level of histological differentiation (lamination). So we can conclude that there is a correlation between LGN volumina and the occurrence of dLGN lamination in members of the same order. This rule cannot be applied generally to species belonging to different orders.