Microsaccadic efficacy and contribution to foveal and peripheral vision

Abstract

Our eyes move constantly, even when we try to fixate our gaze. Fixational eye movements prevent and restore visual loss during fixation, yet the relative impact of each type of fixational eye movement remains controversial. For over five decades, the debate has focused on microsaccades, the fastest and largest fixational eye movement. Some recent studies have concluded that microsaccades counteract visual fading during fixation. Other studies have disputed this idea, contending that microsaccades play no significant role in vision. The disagreement stems from the lack of methods to ascertain the precise effects of microsaccades on vision versus those of other eye movements, as well as a lack of evidence that microsaccades are relevant to foveal vision. Here we developed a novel generalized method, based on mathematical techniques previously employed to assess the strength of connection of two neurons, to determine the precise quantified contribution and efficacy of microsaccades to restoring visibility as compared to other eye movements. Our results indicate that microsaccades are the greatest eye movement contributor to the restoration of both foveal and peripheral vision during fixation. Our method to calculate the efficacy and contribution of microsaccades to perception can determine the strength of connection between any two physiological and/or perceptual events, providing a more powerful estimate of causality than correlation; thus we anticipate wide-ranging applications in neuroscience and beyond.

Meeting abstract presented at VSS 2012