Abstract
Temporal integration and segregation are key elements of visual perception. When two visual events happen in rapid succession, they may not be separable to the visual system and are thus processed as one event. With longer temporal intervals between events, the probability for the events to be temporally segregated increases. Given suitable timing, identical paired-stimulus presentations may result in different outcomes (segregation or integration) on a trial-by-trial basis. We presented two flashes of light in rapid succession at different ISIs (33, 66, 100 and 400ms) while recording MEG. The first stimulus was presented at threshold intensity, while the second stimulus was presented at above-threshold intensity. A total of 17 subjects reported the number of stimuli seen (one or two). A baseline condition with only one pulse was included to minimize bias. To better exclude chance guesses from the analysis, the paired flashes were shown randomly in one of four quadrants. Trials in which subjects identified the wrong quadrant were eliminated. Behaviorally, subjects differed in their ability to correctly discriminate the two pulses, with some needing a much longer ISI in order to reliably detect both stimuli. The difference between timing conditions was reflected in the evoked responses to the two stimulus pulses. In addition, we found a significant correlation between the individual duration of the temporal integration window (as indicated by the individual behavioral performance) of our subjects and their measured resting state alpha frequency. These results provide evidence for a close link between the speed at which visual information is integrated or segregated and the resting rate of neural oscillations in the brain, with a possible connection being the individual speed of the underlying neural substrate.
Meeting abstract presented at VSS 2017