Visual integration during saccadic and pursuit eye movements: the importance of spatial framework.

Three experiments were conducted to clarify the function of spatiotopic and retinotopic visual persistence during pursuit and saccadic eye movements. Exps. 1 and 2 both showed spatiotopic visual integration for both types of eye movements, although shorter stimulus onset asynchrony (SOA) was set in Exp. 2. Exp. 3 was conducted with special attention to the absence of target stimuli when masking stimuli were presented. Although duration of target stimuli and stimulus onset asynchrony in Exp. 3 were longer than those in the first two experiments, analysis contrastively showed retinotopic visual integration during saccades and very low accuracy rates under all conditions during pursuit eye movements. The above indicates that the basis for the functional switching between spatiotopic and retinotopic visual integration may have been the existence of a visual framework for visual integration or the synchronous existence of target and masking stimuli in the visual field, not the duration of target stimuli and stimulus onset asynchrony. Such integration of the reference point may possibly be processed through a higher mechanism and not at the retinal level.