Oddballs that are suppressed or dominant in binocular rivalry are equally processed for the first 300 ms U Roeber1, B N Jack1, R P O’Shea1, A Widmann2, E Schröger2 |
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1Psychology, Southern Cross University, Australia |
| We married two techniques to investigate change detection in early binocular processing: binocular rivalry and oddball stimulation. Binocular rivalry yields unpredictable changes in perception between a continuously-presented image to the right eye and a continuously-presented, different image to the left eye. Oddball stimulation occurs when a standard stimulus is repeatedly presented but occasionally replaced by another, deviant stimulus. Deviants elicit larger negative responses in event-related potentials (ERPs)—the visual mismatch negativity (vMMN)—even when stimulation is not attended. We presented binocular-rivalry stimuli repeatedly for 100 ms on and 100 ms off. Standards were full-contrast, dichoptic, orthogonal gratings; deviants were identical except with reduced contrast and luminance in one eye. Because of binocular rivalry these deviants occurred either to the suppressed or to the dominant eye. We found that, compared to standards, ERPs to deviants showed more negativity at 130 ms and at 270 ms; these are candidate vMMNs. They were of similar amplitude in the dominant eye and in the suppressed eye. Differences in processing between the two types of deviants emerged only after 300 ms. We propose that oddball stimuli are fully processed during binocular rivalry, irrespective of whether they are perceived or not. |
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