How does the brain maintain a stable, continuous perceptual experience in the face of large visual disruptions such as those frequently occurring during blinks and eye movements? Saccadic remapping, a predictive shift in neuronal receptive fields around the time of saccades, has been proposed as an essential neuronal mechanism. In turn, saccadic remapping has been linked to a set of perisaccadic illusions, whereby stimuli flashed briefly around the time of a saccade are mislocalized in space and time. In a recent study, Zimmermann et al. (J Neurophysiol 2014) broadly reproduced similar spatial and temporal mislocalization patterns when the saccade was replaced by a full-field masking interruption. Rather than saccadic compensation alone, such illusions must be due to a more general updating process linking targets of interest across visual interruptions. In this study, we focus more fully on temporal consequences of visual disruptions. Two vertical bars were presented at varying stimulus-onset asynchronies (SOA: -20 to 160 ms in 10 ms increments, furthest vs nearest stimulus), and a full field mask presented at one of three intervals relative to the near stimulus (50, 100 and 150 ms), along with an unmasked condition. Subjects (N=8) maintained fixation throughout the trial, and reported the order in which the two bars appeared. When the second stimulus was presented close to the time of the mask, subjects often reported (30 to 40% of trials on average) that it appeared before the first stimulus, even when the SOA was as large as 150 ms. In a second experiment in which subjects (N=6) also reported response confidence, we obtained similar results analysing only a??confidenta?? responses, indicative of an actual perceptual reversal rather than increased perceptual uncertainty. We offer a speculative explanation in terms of sequential processing of discrete events, and link this to recent results on neuronal oscillations.
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