In mammalian primary visual cortex (V1), integration of the left and right visual scene into a binocular percept derives from convergent ipsi- and contralateral geniculocortical inputs and trans-callosal projections between the two hemispheres. However, the underlying developmental mechanisms remain incompletely understood. Using genetic methods in mice we found that during the days before eye-opening, retinal and callosal activity drives massive apoptosis of GABAergic chandelier cells (ChCs) in the binocular region of V1. Blockade of ChC elimination resulted in a contralateral-dominated V1 and deficient binocular vision. As activity patterns within and between retinas prior to vision convey organization of the visual field, their regulation of ChC density through the trans-callosal pathway may prime a nascent binocular territory for subsequent experience-driven tuning during the post-vision critical period.

Retinal and callosal activity-dependent chandelier cell elimination shapes binocularity in primary visual cortex