On the coordination of saccades with hand and smooth pursuit eye movements

Viac o knihe

Saccades are rapid eye movements that reposition the fovea to focus on different points in the visual field. The coordination of these eye movements with our behavior is crucial. The thesis investigates how this coordination occurs. Part I explores the relationship between eye and hand movements. Previous studies suggest that neural processes coordinate saccades and hand movements by adjusting saccade onset time and speed. However, I argue that the need to process relevant visual information at the saccade endpoint is sufficient to cause these adjustments. Thus, changes in saccade timing and speed may reflect the importance of vision at the target location rather than a mechanism for coordinating eye and hand movements. Part II focuses on the interplay between smooth pursuit and saccadic eye movements. Smooth pursuit involves slow eye movements that track moving objects, and the eyes often switch between smooth pursuit and saccades, indicating a close coupling of their control processes. Evidence shows that smooth pursuit can systematically influence the onset time of saccades. This influence may arise from two mechanisms: a bias in visual attention toward the direction of pursuit for saccades during smooth pursuit, and an inhibitory mechanism for saccades directed at moving targets. The latter is supported by findings that the occurrence and latency of saccades to moving targets depend on their eccentricity and velocity.