Fronto-parietal cortex mediates perceptual transitions in bistable perception V Weilnhammer, K Ludwig, G Hesselmann, P Sterzer |
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Visual Perception Laboratory, Department of Psychiatry Charité Campus Mitte, Berlin, Germany
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| During bistable vision, perception oscillates between two mutually exclusive percepts while the incoming sensory information remains constant. Greater blood oxygen level dependent (BOLD) responses in fronto-parietal cortex have been shown to be associated with perceptual transitions as compared to “replay” events designed to closely match bistability in both perceptual quality and timing. It has remained controversial, however, whether this enhanced activity reflects causal influences of these regions on processing at the sensory level or, alternatively, an effect of stimulus differences that result, e.g., in longer durations of perceptual transitions in bistable perception compared to replay conditions. Using a rotating Lissajous figure in a functional magnetic resonance imaging (fMRI) experiment, we controlled for potential confounds of differences in transition duration and confirmed previous findings of greater activity in frontal and parietal brain areas for transitions during bistable perception. In addition, we applied Dynamic Causal Modeling (DCM) to identify the neural model that best explains the observed BOLD signals in terms of effective connectivity. We found that enhanced activity levels for ambiguous events are most likely mediated by increased top-down connectivity from frontal to visual cortex, thus arguing for a mediating role of fronto-parietal cortex in perceptual transitions during bistable perception. |
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