Abstract
Our eyes move continually even while we fixate our gaze on an object. If fixational eye movements are counteracted, our perception of stationary objects fades completely, due to neural adaptation. Some studies have suggested that fixational microsaccades refresh retinal images, thereby preventing adaptation and fading. However, other studies disagree, and so the role of microsaccades remains unclear. Here we correlate, for the first time, visibility during fixation to the occurrence of microsaccades. We asked subjects to indicate when Troxler fading of a peripheral target occurs, while simultaneously recording their eye movements with high precision. We found that before a fading period, the probability, rate and magnitude of microsaccades decreased. Before transitions towards visibility, the probability, rate and magnitude of microsaccades increased. These results reveal a direct link between suppression of microsaccades and fading, and suggest a causal relationship between microsaccade production and target visibility during fixation.
Experiments funded through a startup award from the Barrow Neurological Foundation to SM-C.