Keeping Track of Locations in Space

The visual system compensates for the effect of eye movements through a process known as remapping. Previously, we have shown that when an eye movement is about to shift a stimulated location from the blind to the sighted visual field of hemianopic participants, sensitivity at that location is elevated, which we attribute to remapping from the blind to the sighted field (Ritchie, Hunt, and Sahraie, 2012). Here, we show that a patient whose damage includes the thalamus cannot detect a stimulus in his blind field and does not show evidence of remapping. We have devised a task which taps into the maintenance of spatial information across saccades and shows that normal observers and those patients who can remap information from their blind to sighted field can also maintain information regarding spatial locations across saccades. However, in the case of the patient without evidence for remapping, performance in the blind field is considerably impaired, compared with that of his sighted field. The findings suggest that remapping contributes to our ability to keep track of spatial locations across saccades.