Microsaccade Selectivity as Discriminative Feature for Object Decoding

Abstract

Microsaccades, a form of fixational eye movements, maintain visual stability during stationary observations. Previous studies have provided valuable insights into the relationship between microsaccade characteristics and external stimuli. However, the dynamic nature of microsaccades provides an opportunity to explore the mechanisms of information processing, particularly object decoding. This study examines the modulation of microsaccadic rates by different stimulus categories. Our experimental approach involves an analysis of microsaccade characteristics in monkeys and human subjects engaged in a passive viewing task. The stimulus categories comprised four primary categories: human, animal, natural, and man-made. We identified distinct microsaccade patterns across different stimulus categories, successfully decoding the stimulus category based on the microsaccade rate post-stimulus distribution. Our experiments demonstrate that stimulus categories can be classified with an average accuracy and recall of up to 85%. Our study found that microsaccade rates are independent of pupil size changes. Neural data showed that category classification in the inferior temporal (IT) cortex peaks earlier than microsaccade rates, suggesting a feedback mechanism from the IT cortex that influences eye movements after stimulus discrimination. These results exhibit potential for advancing neurobiological models, developing more effective human-machine interfaces, optimizing visual stimuli in experimental designs, and expanding our understanding of the capability of microsaccades as a feature for object decoding.