NEUROFILAMENT PROTEINS IN Y-CELLS OF THE CAT LATERAL GENICULATE-NUCLEUS - NORMAL EXPRESSION AND ALTERATION WITH VISUAL DEPRIVATION

We examined neurofilament staining in the normal and visually deprived lateral geniculate nucleus (LGN), using the SMI-32 antibody. This ant ibody preferentially stains LGN cells that display the morphological c haracteristics of Y-cells. The soma sizes of SMI-32-stained cells were consistent with those of the overall population of Y-cells, and the G olgi-like staining of their dendrites revealed a radial distribution t hat often crossed laminar boundaries. Labeled cells were distributed w ithin the A laminae (primarily near laminar borders), the magnocellula r portion of the C laminae, and the medial intralaminar nucleus, but t hey were absent in the parvocellular C laminae. Electron microscopic e xamination of SMl-32-stained tissue revealed that staining was confine d to somata, dendrites, and large myelinated axons. Retinal synapses o n SMI-32-labeled dendrites were primarily simple axodendritic contacts ; few triadic arrangements were observed. In the LGN of cats reared wi th monocular lid suture, SMI-32, staining was decreased significantly in the A laminae that received input from the deprived eye. Dephosphor ylation of the tissue did not alter the cellular SMI-32 staining patte rns. Analysis of staining patterns in the G laminae and monocular zone of the A laminae suggests that changes in the cytoskeleton after lid suture reflect cell class and not binocular competition. Taken togethe r, the results from normal and lid-sutured animals suggest that the ca t LGN offers a unique model system in which the cytoskeleton of one cl ass of cells can be manipulated by altering neuronal activity.