Blinks slow memory-guided saccades

Area of Science:

• Neuroscience
• Ophthalmology
• Motor Control

Background:

• Memory-guided saccades are known to be slower than visually guided saccades.
• The prevailing theory attributes this slowing to reduced neural drive in the superior colliculus due to the absence of visual input.

Purpose of the Study:

• To investigate the role of gaze-evoked blinks in the slowing of memory-guided saccades.
• To compare the frequency and impact of blinks during memory-guided versus visually guided saccades.

Main Methods:

• Recorded gaze-evoked blinks in three monkeys during both visually guided and memory-guided saccade tasks.
• Analyzed saccade kinematics, comparing performance with and without blinks.

Main Results:

• Gaze-evoked blinks occurred more frequently during memory-guided saccades.
• Blinking disrupted the relationship between peak and average saccade velocity.
• The slowing of memory-guided saccades was significantly greater when blinks were present.

Conclusions:

• Gaze-evoked blinks contribute substantially to the slowing of memory-guided saccades.
• Interactions between saccade and blink circuits increase saccade trajectory curvature and decrease velocity.
• Blink amplitude correlates with increased saccade curvature and slowing.