Evidence for functional flexibility in developing cortex from studies of blindness

How rigidly does innate architecture constrain function of developing cortex? What is the contribution of early experience? We address these questions by reviewing advances in the study of occipital function in people born blind. In blindness, visual cortices are active during auditory and tactile tasks. What such ‘cross-modal’ plasticity tells us about cortical flexibility is debated. On the one hand, there is evidence that visual networks of blind people respond to higher cognitive information, such as grammar of spoken sentences, suggesting drastic repurposing. On the other hand, it is suggested that occipital areas switch their modality of input but continue to perform the same perceptual functions (e.g., face recognition) in blindness. We find little support for this ‘modality-switching’ account. Rather, functional reorganization results from takeover by top-down fronto-temporal and fronto-parietal higher-cognitive networks, which are a major source long-range input to the visual system. Visual cortex function differs across blind and sighted populations, suggesting human cortex is highly functionally flexible early in life. Cortical function is constrained by innate architecture but heavily shaped by behavioral needs and experiences of the individual. Rather than predicting the function of cortical areas in minority populations from the adult majority, we advocate a developmental approach. notReviewed other