Experience-dependent development and maintenance of binocular neurons in the mouse visual cortex

ABSTRACT The normal development of neuronal circuits requires both hard-wired gene expression and experience. Sensory processing, such as vision, is especially sensitive to perturbations in experience. However, the exact contribution of experience to neuronal visual response properties and binocular vision remains unknown. To determine how visual response properties develop in vivo , we used single cell resolution two-photon calcium imaging of mouse binocular visual cortex at multiple time-points after eye opening. Few neurons are binocularly responsive immediately after eye opening and respond solely to either the contralateral or ipsilateral eye. Binocular neurons emerge during development, which requires visual experience, and show specific tuning of visual response properties. As binocular neurons emerge, activity between the two eyes becomes more correlated in the neuropil. Since experience-dependent plasticity requires the expression of activity-dependent genes, we determined whether the plasticity gene Arc mediates the development of normal visual response properties. Surprisingly, rather than mirroring the effects of visual deprivation, mice that lack Arc show increased numbers of binocular neurons during development. Strikingly, removing Arc in adult binocular visual cortex increases the numbers of binocular neurons and recapitulates the developmental phenotype, suggesting cortical circuits that mediate visual processing require ongoing experience-dependent plasticity. Thus, experience is critical for the normal development and maintenance of circuits required to process binocular vision.