FIGURE 4.

Labeling of ocular dominance columns (ODCs) and horizontal axonal connections in striate cortex (area V1) of a normal primate. [³H] proline was injected into the vitreous cavity of one eye and transported anterogradely from eye-to-V1 layer 4C, labeling ODC territory belonging to the injected eye. Unlabeled ODC territory (every-other row of ODCs) belonged to the fellow, noninjected eye. A second label, biotinylated-dextran-amine (BDA), was injected into individual ODCs; it was transported by axonal, horizontal projections, from the site of injection, to label pyramidal neurons in neighboring ODCs, which connected to the injected ODC. Thin, tangential sections through (binocular) layer 4B and (monocular) layer 4C were aligned and overlayed for analysis of horizontal connections.