Saccadic Remapping in Hemianopia

Abstract

We experience visual stability despite shifts of the visual array across the retina produced by eye movements. The visual system predicts the retinal consequences of saccades through a process known as saccadic remapping. We explored remapping in damaged visual cortex by presenting a stimulus in the blind field of a patient with hemianopia. Reported awareness was elevated when a saccade was about to bring the stimulated location into the sighted field, even though the stimulus was removed before the saccade began and so never stimulated the sighted field. The presence of a blind-field stimulus before saccade also increased sensitivity to a near-threshold sighted-field stimulus that was presented at the same spatial location after saccade. The results suggest early visual areas are not necessary for remapping, but play a role in verifying predictions about the retinal positions of post-saccadic targets generated by remapping.