Previous neurophysiological studies showed that retinal lesions in adult mammals produce shifts in the corresponding cortical receptive fields. Do similar shifts in cortical receptive fields occur at the physiological and pathological blind spots in humans? Based on psychophysical performance around blind spots, I will argue against such shifts of the corresponding cortical receptive fields. This argument will be based on three main sets of experiments. The first set looked for length distortions across the blind spot and did not find any. The second set showed that dichoptic lateral interactions at the blind spot are similar to those found in peripheral vision away from physiological blind spots. The last set showed the same for a pathological retinal blind spot.

A related question is: where in the visual pathway do these lateral interactions occur? I will compare some of our results from other psychophysical experiments involving lateral interactions to previous neurophysiological results and argue that the long-range horizontal connections in primary visual cortex are the likely substrate for these interactions. Finally, I will present two cases who showed unusual binocular lateral interactions, one with unknown pathology and the second with lesions in extrastriate cortex.