On the Role of Attention in Binocular Rivalry: Electrophysiological Evidence

Abstract

During binocular rivalry visual consciousness fluctuates between two dissimilar monocular images. We investigated the role of attention in this phenomenon by comparing event-related potentials (ERPs) when binocular-rivalry stimuli were attended with when they were unattended. Stimuli were dichoptic, orthogonal gratings that yielded binocular rivalry and dioptic, identically oriented gratings that yielded binocular fusion. Events were all possible orthogonal changes in orientation of one or both gratings. We had two attention conditions: In the attend-to-grating condition, participants had to report changes in perceived orientation, focussing their attention on the gratings. In the attend-to-fixation condition participants had to report changes in a central fixation target, taking attention away from the gratings. We found, surprisingly, that attending to rival gratings yielded a smaller ERP component (the N1, from 160–210 ms) than attending to the fixation target. To explain this paradoxical effect of attention, we propose that rivalry occurs in the attend-to-fixation condition (we found an ERP signature of rivalry in the form of a sustained negativity from 210–300 ms) but that the mechanism processing the stimulus changes is more adapted in the attend-to-grating condition than in the attend-to-fixation condition. This is consistent with the theory that adaptation gives rise to changes of visual consciousness during binocular rivalry.

A Neural Network Approach to fMRI Binocular Visual Rivalry Task Analysis

“…The behavioral data showed that the mean perception dominance duration was variable between subjects and consistent with the previous studies using similar stimuli [14], although an EEG study reported a shorter perception dominance duration using rotating gratings as stimuli [26]. Interestingly, we noticed that the worst performance of our brain states classifier was obtained from subjects 5 and 6, who experienced shorter mean perception durations (respectively 2.57 s and 1.78 s); we speculate that it may be harder to decode a signal when perception changes are too quick.…”

Predicting Visual Consciousness Electrophysiologically from Intermittent Binocular Rivalry

“…There is no necessary contradiction here if it is assumed that Lamme’s two stages operate in parallel. Perhaps what is surprising in the light of our results is just how late the predictive activity is, at the time of the second, and not the first (100 ms after an event) major ERP component to have been shown to be a neural correlate of consciousness in binocular rivalry [20], [64], [65] and in masking [111].…”

“…We re-referenced the EEG data offline to the linked earlobes. We did this to allow comparison with earlier work on multistable visual phenomena that also used linked ears [40], [41], [42], [43], [64], [65], [82], [83]. We applied a 0.3–35 Hz bandpass filter (Kaiser windowed sinc FIR filter, 1857 points, Kaiser window beta 5.65326) to the data before analysis.…”

“…The other line of research that guided our search for a ROI was into ERPs during binocular rivalry when the event is a change in the orientation of one of the rival gratings to be the same as the other grating [20], [62], [63], [64], [65]. This approach yields physically identical stimuli (i.e., a change in the orientation of one grating) that differ in visual consciousness: when the change happens in the dominant eye, the change is visible; when the change happens in the suppressed eye, the change is harder to see, if not invisible.…”

Does visual attention drive the dynamics of bistable perception?

“…The notion of a preserved marker of switches in V1 is consistent with recent optical imaging work in monkeys, showing that an alternating pattern of V1 activity in response to rivalry stimulation remains even under general anesthesia (Xu et al, 2016). In potentially related work, Roeber, Veser, Schröger, & O'Shea, 2011 measured event-related potentials (ERPs) and discovered a difference in response to rivalrous stimuli compared to non-rivalrous stimuli; a difference that remained even if the stimuli were unattended (also see Katyal, Engel, He, & He, 2016). This may suggest similar treatment of attended and unattended rival stimuli by the visual system (i.e.…”