Thus, the visual motion information across saccades was integrated in spatiotopic coordinates and represented in the activity of MST neurons. A delayed-saccade paradigm further revealed that memory remapping in MST was linked to the saccade itself, rather than to a shift in attention. These findings suggest that the responses of such MST neurons after saccades were evoked by a memory of the stimulus that had preexisted in the postsaccadic RFs (“memory remapping”).
In contrast, most MST neurons increased their firing rates when a saccade brought the location of the visual stimulus into their RFs, where the visual stimulus itself no longer existed. For MT neurons, virtually no response was observed after the saccade, suggesting that the responses of these neurons simply reflect the reafferent visual information. Different characteristic responses emerged when the moving visual stimulus was turned off before the saccades. We found that the location of the RFs moved with shifts of eye position due to saccades, indicating that motion-sensitive neurons in both areas have retinotopic RFs across saccades.
To investigate how the visual system deals with localization of moving visual stimuli across saccades, we observed spatiotemporal changes of receptive fields (RFs) of motion-sensitive neurons across periods of saccades in the middle temporal (MT) and medial superior temporal (MST) areas. Perception of a stable visual world despite eye motion requires integration of visual information across saccadic eye movements.