Age-Related Changes in Soma Size of Y Neurons in the Cat Dorsal Lateral Geniculate Nucleus: Dorsoventral and Centroperipheral Gradients

The postnatal developmental dynamics of neurons in the cat dorsal lateral geniculate nucleus (dLGN) was studied using a selective marker of Y neurons, the monoclonal antibody SMI-32 against non-phosphorylated heavy-chain neurofilaments. The neuronal soma area was measured within various functional regions of the nucleus. The following three major peculiarities of the internal organization of the dLGN layers and retinotopic regions were revealed: (1) an ascending dorsoventral soma area gradient of SMI-32-immunopositive neurons, increasing with age; (2) a descending centroperipheral soma area gradient of SMI-32-immunopositive neurons, decreasing with age; (3) smaller size of neurons located in the lower visual field representation along the vertical meridian. The data suggest heterogeneity of the population of Y neurons and heterochronicity of its postnatal development.