Abstract
Theories of visual stability have emphasized either the need to construct a continuously accurate, retinocentric representation of visual space or a relative localization based on landmarks, specifically the saccade target or nearby objects (Currie et al., 2000 Perception & Psychophysics; Deubel, 2004 Visual Cognition). Although both theories may rely on corollary discharge (Sommer & Wurtz, 2006 Nature, Hamker, 2005 Visual Cognition), the first theory has been linked to the observation of predictive remapping of receptive fields (RFs), whereas an electrophysiological manifestation in terms of dynamic RF changes has not been proposed for a saccade target theory. We have developed a quantitative computational model related to the saccade target theory of visual perception. The observation that objects, located around the saccade target, are special is explained by a spatially selective corollary discharge signal that is directed to the location of the saccade target in multiple visual areas. This occulomotor feedback signal changes the gain of neurons and thus, in addition, affects the RF structure. Our model makes quantitative predictions about perisaccadic RF dynamics depending on the RF center and the saccade target location. Interestingly, the computed model RF shifts are similar to those of predictive remapping when the direction of the vector from the RF center to the saccade target is in the same direction as the saccade vector. However, both theories offer completely different predictions when the vector from the RF center to the saccade target points in the opposite direction than the saccade vector. Thus, we suggest testable experiments that allow to determine the cause of perisaccadic RF effects in different brain areas, which may lead to a deeper understanding of perisaccadic perception and of the subjective experience of visual stability.
This work was supported by the German Science Foundation DFG HA2630/4