Using ocular dominance to infer the depth of the visual input layers of V1 in behaving macaque monkey

The goal of this study was to use the ocular dominance properties of multiple unit activity in area V1 of the visual cortex of the behaving rhesus monkey to infer the depth of the visual input layers. Multiple unit activity was examined with a recording electrode at different depths (in 100 micrometer increments) within V1 for responses to a visual stimulus presented to the dominant and non-dominant eye. The cortical depth at which there was a maximal difference in unit firing rate between the dominant and non-dominant eye was used to infer the depth of the visual input layers of V1. This depth was found to vary from 0.8 to 1.2 mm below the cortical surface. This range of depths overlaps with the approximate location of lamina IVc, which is the major recipient of visual fibres from the lateral geniculate nucleus.