Regular patchy distribution of cytochrome oxidase staining in primary visual cortex of macaque monkey

Abstract

In two preliminary studies, normal macaque¹ and squirrel monkey^2,3 striate cortex cut parallel to the surface and stained for cytochrome oxidase (a mitochondrial enzyme) showed a striking pattern of regularly spaced patches. This was surprising, since until then no physiological or anatomical studies had suggested such a patchy organization. In the present study in the macaque we found that the patches were arranged in rows spaced about 350 µm apart. When one eye was injected with tritiated proline the rows of patches in layers II and III lay in register with the ocular-dominance bands seen autoradiographically in layer IVc. Removing one eye caused the patches in every other row to shrink and blanch. The rows of patches are therefore centred on the ocular dominance columns. Regions labelled by 2-deoxyglucose autoradiography after stimulating one eye with black-and-white stripes in all orientations consisted of rows of patches that lay in register with the cytochrome oxidase patches in every other row. On stimulating monkeys with stripes of a single orientation, the deoxyglucose-labelled regions formed a lattice that included the cytochrome oxidase patches but was more extensive. Thus either the deoxyglucose is not labelling the orientation columns at all, or the orientation columns coalesce in the areas marked by the cytochrome oxidase stain.