Spatial metric in blindness: behavioural and cortical processing

Visual modality dominates spatial perception and, in lack of vision, space representation might be altered. Here we review our work showing that blind individuals have a strong deficit when performing spatial bisection tasks ( Gori et al., 2014 ). We also describe the neural correlates associated with this deficit, as blind individuals do not show the same ERP response mimicking the visual C1 reported in sighted people during spatial bisection ( Campus et al., 2019 ). Interestingly, the deficit is not always evident in late blind individuals, and it is dependent on blindness duration. We report that the deficit disappears when one presents coherent temporal and spatial cues to blind people. This suggests that they may use time information to infer spatial maps ( Gori et al., 2018 ). Finally, we propose a model to explain why blind individuals are impaired in this task, speculating that a lack of vision drives the construction of a multi-sensory cortical network that codes space based on temporal, rather than spatial, coordinates.