Identification of Double-Step Saccades Elicited by Auditory Double-Step Stimuli

Voluntary Saccadic eye movements can have visual, auditory, and auditory-visual bisensory origins. An experiment may be defined to examine how changing the type of sensory inputs and the number of them in a sequence reveals the type of the saccade generated by the oculomotor system; here in deemed single-step or double-step. This work reports design of experiments of double-step auditory stimuli played for human subjects, recording triggered saccadic eye movements, detecting each saccade, as well as estimating the saccade response characteristics, namely duration and latency. 

Based on the latency, then, it determines the type of the generated saccade by the subject through a clustering technique. We found that when doubling the amplitude of the two separate steps in double-step inputs, while keeping their duration unchanged, the number of triggered double-step saccades rises. The hindsight from this finding is useful because it can guide future stimulus designs to trigger specific saccade types in humans. Such designs, in turn, demystify the nature of dominant saccadic response as we explore the changes of sounds in any controlled environment.