Differences in primary visual cortex predict performance in local motion detection in deaf and hearing adults

摘要

Background The alteration of sensory experience can result in an enhancement in other sensory modalities. For example, congenitally deaf adults perform better in peripheral motion detection tasks. Recent work has indicated that peripheral motion sensitivity is correlated with structural changes in the retina in deaf and hearing individuals (Codina et al., PLoSOne, 2011). Moreover, electrophysiological signals in peripheral retina and visual cortex are larger and faster in deaf than hearing adults (Baseler et al., SFN 2013). This leads to the prediction that the peripheral representation in primary visual cortex should also reflect differences between deaf and hearing individuals. Methods Participants included eleven congenitally, profoundly deaf adults and eleven matched hearing controls, all without visual deficits. FMRI retinotopic mapping was performed using stimuli extending out to +/-72?° to include the far peripheral visual field, where behavioral sensitivity differences are greatest in deaf adults. Motion detection was also measured in the same participants using a 2 AFC task with dot patterns at varying eccentricities.. Structural measurements of the V1 representation at each eccentricity were correlated with performance on the motion detection task in each individual. Results In V1, the ratio of peripheral to central visual field representation (volume and area) is significantly larger in deaf than hearing participants. In addition, the area of the peripheral representation in V1 predicted performance in peripheral motion detection in both deaf and hearing individuals. Conclusions Individual differences in visual maps in V1 appear to influence peripheral motion sensitivity, and these maps may be affected by differences in visual experience brought about by hearing loss.