Countermanding saccades with auditory stop signals: testing the race model

Area of Science:

• Neuroscience
• Cognitive Psychology
• Ophthalmology

Background:

• Human saccades are rapid eye movements crucial for visual processing.
• Investigating the precise timing and mechanisms of saccade inhibition is key to understanding motor control.
• Previous research primarily used visual stop signals to probe saccade inhibition.

Purpose of the Study:

• To investigate the control of human saccades using an auditory stop signal paradigm.
• To estimate the stop signal processing time (SSPT) required to inhibit a saccade.
• To explore the effect of stop signal location on inhibition effectiveness and saccade characteristics.

Main Methods:

• A stop signal paradigm where participants made saccades to visual targets.
• An auditory stop signal was presented at variable delays to test inhibition.
• The race model was used to estimate the average time needed to inhibit a saccade (SSPT).

Main Results:

• Estimated SSPT ranged from 50 to 100 ms, shorter than with visual stop signals.
• The position of the auditory stop signal did not affect countermanding effectiveness.
• Saccadic response times were largely consistent with race model predictions, with some violations observed.
• A tendency towards hypometric saccades was noted for uninhibited responses.

Conclusions:

• Auditory stop signals allow for rapid inhibition of human saccades.
• Saccade inhibition mechanisms appear robust across different stop signal locations.
• Findings provide insights into the neural processes underlying motor inhibition and potential deviations.