Presaccadic suppression is reduced for antisaccades

Area of Science:

• Neuroscience
• Visual Perception
• Oculomotor Control

Background:

• Visual sensitivity decreases before and during saccadic eye movements.
• The exact mechanisms for this saccadic suppression are not fully understood.
• One hypothesis suggests extra-retinal signals, like corollary discharge, modulate visual processing during saccade preparation.

Purpose of the Study:

• To investigate if saccadic suppression depends on the neural processes of movement planning.
• To test if different types of saccades (pro- vs. anti-saccades) exhibit different suppression dynamics.
• To determine if motor preparation signals contribute to perceptual suppression.

Main Methods:

• Participants performed pro- and anti-saccade tasks.
• Contrast sensitivity was measured using briefly presented horizontal gratings.
• Gratings were presented at various times relative to saccade onset to map suppression timing.

Main Results:

• A robust increase in contrast thresholds (saccadic suppression) was observed around saccade onset for both saccade types.
• Suppression was significantly reduced 50ms before saccade onset for anti-saccades compared to pro-saccades.
• This difference was not attributable to saccade kinematics like amplitude or velocity.

Conclusions:

• The temporal characteristics of saccadic suppression are influenced by the type of saccade being prepared.
• Findings support the role of active motor preparatory signals in initiating perceptual suppression.
• This provides evidence for the corollary discharge hypothesis in modulating visual processing during eye movements.