Self-Oscillator Model of Bistable Perception with Interrupted Ambiguous Stimulus Explains Percept Stabilization and Reversal Rate Characteristics

Kurzfassung

Experiments with periodically interrupted ambiguous stimulus (e.g. the Necker cube) with short off-times (< 1 s) exhibit a maximum of the percept reversal rate of R ca. 36 min-1 at stimulus-off time toff ca. 200 – 300 ms (with ton = const = 300 ms (Orbach et.al.1966)(Kornmeier & Bach 2007). The subjective percept is stabilized with increasing toff-time due to recovery from fatigue. In this contribution it is shown that these results can be explained by a simple nonlinear dynamics attention fatigue model with delayed feedback (adaptive gain) which was recently used for explaining long range correlations of the reversal time series (Gao et.al. 2006)(Fürstenau 2010). The present model is related to the Synergetic order parameter approach of Ditzinger & Haken (1989). A reentrant phase oscillator equation (circle map) describes the dynamics of the perception state (order parameter) with feedback through the attention (gain) control parameter. It was shown earlier that the present model correctly predicts a number of features of multistable percept dynamics, e.g. the the hysteresis behavior between stationary perception states and theGamma-distribution of the percept dwell time statistics Here we demonstrate that also the stimulus - off induced percept stabilization and reversal rate maximum of interrupted stimulus experiments is correctly predicted. The maximum separates the nonstationary regime with toff < percept transition time ca. 200 ms from the stationary percept stabilization regime (toff ca. 200 ms). The absolute toff - value is determined by the time constants (fatigue, recovery, feedback delay) and noise power as parameters of the three coupled perception-attention-memory (PAM-) equations. A mapping of the PAM equations to basic Thalamo-Cortical reentrant loops is suggested. References Fürstenau, Norbert (2010). A nonlinear dynamics model for simulating long range correlations of cognitive multistability. Biol. Cybern., vol. 103. (3) 175-198 Gao, J.B., Merk, I., Tung W W, Billok V, White, K.D., Harris J G, Roychowdhury V P. (2006a) Inertia and memory in visual perception. Cogn. Process 7 105-112 Ditzinger, T., Haken, H. (1989). Oscillations in the Perception of Ambiguous Patterns. Biol. Cybern. ( 61) 279-287 Orbach. J., Zucker, E., Olson, R. (1966). Reversibility of the Necker Cube: VII. Reversal rate as a function of figure-on and figure-off durations. Percept. and Motor Skills (22), 615-618 Kornmeier, J., Ehm, W. Bigalke, H., Bach, M. (2007): Discontinuous presentation of ambiguous figures: How interstimulus-interval durations affect reversal dynamics and ERP’s. Psychophysiology, 44, 552-560