Tuesday 25 May 2021: Dynamic external noise sequences modulate perception in binocular rivalry
Daniel Baker - University of York
https://Universityofexeter.zoom.us/j/97732074999?pwd=Sithd1g3UFVxRDdHY0l0MVZXb1RQZz09 Meeting ID: 977 3207 4999 Password: 916657 13:30-14:30
Neural systems are inherently noisy, and this noise can affect our perception from moment to moment. This is particularly apparent in binocular rivalry, where perception of competing stimuli shown to the left and right eyes alternates over time. In a series of psychophysical experiments, rivalry was modulated using external noise stimuli of various rates and amplitudes. An initial result was that stimuli with 1/f fractal properties in space and time tend to dominate perception, supporting the idea that perceptual processes are tuned to the statistics of the natural environment. Next, sequences of bandpass-filtered external noise with different peak temporal frequencies were presented twice, and the consistency of percepts across repetitions was assessed. External noise modulations of sufficiently high contrast increased consistency scores above baseline, and were most effective at 1/8Hz. A dynamic computational model of rivalry in which internal noise has a 1/f temporal amplitude spectrum, and a standard deviation of 16% contrast, provided the best account of the data. This novel experimental paradigm provides detailed estimates of the dynamic properties of internal noise during binocular rivalry, and by extension the stochastic processes that drive our perception and other types of spontaneous brain activity.
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