Zero correlation is not a hallmark of perceptual bistability: Variation in percept duration is driven by noisy neuronal adaptation

摘要

When the sensory system is subjected to ambiguous input perception involuntarily alternates between alternative interpretations in a seemingly random fashion. Although it is clear that neuronal noise (on microsecond time scale) must play a role in the dynamics of perceptual alternations, the neural mechanism for the generation of randomness at the slow time scale of the percept durations (multiple seconds) is unresolved. Here significant non-zero serial correlations are reported in series of visual percept durations (for the first time accounting for duration impurities caused by reaction time, drift, and incomplete percepts). This refutes a general belief that a Poisson process governs perceptual alternations and that zero serial correlation is a hallmark of binocular rivalry. Comparing different stimuli, we found that serial correlations for perceptual rivalry using structure-from-motion ambiguity were smaller than for binocular rivalry using orthogonal gratings. After considering a spectrum of computational models it is concluded that noise in adaptation of percept-related neurons cause the serial correlations. This work bridges, in a physiologically plausible way, widely appreciated deterministic modelling and randomness in experimental observations of visual rivalry.