Evidence for the existence and development of visual inhibition in humans

Neural inhibition forms a major mechanism by which the nervous system refines and elaborates its input. Several recent experiments have demonstrated the existence of inhibition between orientation-selective cells of the primary visual cortex of the cat and although the precise function of this inhibition is uncertain, there is evidence that it enhances orientation tuning and that it is involved in pattern recognition. Here we report a series of experiments which, on the basis of evoked potential responses to oriented stimuli, suggest that similar processes may exist in humans. Recordings from young infants further suggest that the machinery which mediates orientation-specific interactions may not be functional at birth, but develops only after 6-8 months.