Cortical binocularity in infants

The primate visual cortex, including that of man, receives separate input from each eye and these interact in binocular cortical neurones. This organization is known to be vulnerable to disruption in early life1. To understand the development of human visual cortex, and to detect and assess disorders of binocular function at the earliest possible age, a robust method is needed for detecting binocular interactions in the infant's visual system. We have done this by recording cortical visual evoked responses (VERs) to the onset and offset of binocular correlation in a large-screen dynamic random dot display. We report here that, in general, the human infant has a functional binocular visual cortex by 3 months of age, with some individuals showing cortical binocularity at an earlier age.