Eye movements reset visual perception

Abstract

Human vision uses saccadic eye movements to rapidly shift the sensitive foveal portion of our retina to objects of interest. For vision to function properly amidst these ballistic eye movements, a mechanism is needed to extract discrete percepts on each fixation from the continuous stream of neural activity that spans fixations. The speed of visual parsing is crucial because human behaviors ranging from reading to driving to sports rely on rapid visual analysis. We find that a brain signal associated with moving the eyes appears to play a role in resetting visual analysis on each fixation, a process that may aid in parsing the neural signal. We quantified the degree to which the perception of tilt is influenced by the tilt of a stimulus on a preceding fixation. Two key conditions were compared, one in which a saccade moved the eyes from one stimulus to the next and a second simulated saccade condition in which the stimuli moved in the same manner but the subjects did not move their eyes. We find that there is a brief period of time at the start of each fixation during which the tilt of the previous stimulus influences perception (in a direction opposite to the tilt aftereffect)--perception is not instantaneously reset when a fixation starts. Importantly, the results show that this perceptual bias is much greater, with nearly identical visual input, when saccades are simulated. This finding suggests that, in real-saccade conditions, some signal related to the eye movement may be involved in the reset phenomenon. While proprioceptive information from the extraocular muscles is conceivably a factor, the fast speed of the effect we observe suggests that a more likely mechanism is a corollary discharge signal associated with eye movement.

Nonmonotonic spatial structure of interneuronal correlations in prefrontal microcircuits

“…The difference in the structure of functional connectivity between visual stimulation and intertrial periods across anesthesia and awake states could be attributed to the lack of saccadic eye movements in intertrial periods during anesthesia. Saccadic eye movements reset visual perception ( 38 ), and their absence could create a persistent network state, showing no reset, resulting in very similar patterns of correlations during visual stimulation and intertrial periods.…”

Saccadic modulation of stimulus processing in primary visual cortex

“…While previous studies have suggested that post-saccadic increases in visual neuron firing rates might reflect a window of enhanced processing of the stimuli introduced by saccades 9 13 , our finding that these firing rate increases are accompanied by decreased stimulus selectivity argues against this. If perisaccadic modulation in V1 serves to reset processing in the cortical network (such as through ‘phase-resetting' of ongoing network oscillations 4 ), such synchronized firing rate modulations may help to parse stimuli presented during separate fixations 59 , and ultimately integrate them into a seamless visual percept.…”

The effects of fast disparity adjustment in gaze-controlled stereoscopic applications

“…200Hz) eyetrackers with low latency may potentially allow to predict saccadelanding positions at the beginning of a saccade using a ballistic model [Komogortsev and Khan 2008]. Being able to estimate the future gaze position would then allow to perform the disparity adjustments within the time window of a saccade during which the stream of visual processing is disrupted [Paradiso et al 2012]. However, avoiding latency is a hard problem and requires that it is being traded off against a much lower accuracy in the determination of the attended depth plane.…”