Postsaccadic target blanking prevents saccadic suppression of image displacement

Area of Science:

• Neuroscience
• Cognitive Psychology
• Vision Science

Background:

• High thresholds for detecting visual target displacement during saccadic eye movements suggest limited positional information storage across saccades.
• The visual system's ability to track objects during rapid eye movements is a complex and not fully understood process.

Purpose of the Study:

• To investigate whether post-saccadic target blanking enhances sensitivity to visual displacement.
• To explore the temporal dynamics of visual sensitivity changes related to saccadic eye movements.
• To propose a model explaining how the visual system processes target location after saccades.

Main Methods:

• Psychophysical experiments involving saccadic eye movements and controlled visual target displacements.
• Manipulation of target visibility (blanking) before, during, and after saccades.
• Comparison of displacement detection performance under different blanking conditions and a fixation control.

Main Results:

• Post-saccadic target blanking (50-300 ms) significantly restored sensitivity to visual displacement, with reliable detection of small displacements (0.33 deg).
• Performance with blanking during fixation was inferior to that during saccades, indicating a saccadic enhancement of displacement sensitivity.
• Delayed blanking or pre-saccadic blanking resulted in reduced or weaker effects, highlighting the importance of post-saccadic visual input.

Conclusions:

• The visual system exhibits enhanced sensitivity to image displacement immediately following a saccade when the target is temporarily absent.
• A model is proposed where the visual system searches for a post-saccadic target within a spatiotemporal window, utilizing extraretinal signals when stationarity is broken.