Simulation of spontaneous perception switching with a nonlinear dynamics model using perception-attention-memory coupling

Kurzfassung

Simulation results of bistable perception due to ambiguous visual stimuli are presented which are obtained with a behavioral nonlinear dynamics model using perception–attention– memory (PAM) coupling. It predicts long range correlations of the perceptual duration times in agreement with recent experimental results of Gao et al. (2006) via determination of the self similarity (Hurst) parameter H (Kettani and Gubner 2006) of the reversal time series. The basic model couples the dynamics of a macroscopic perception state order parameter with an adaptive attention (feedback gain) control parameter with additive band limited white noise (Fürstenau 2006). A minimum formal architecture is proposed which allows for mapping of macroscopic thalamo-cortical structures relevant for perception and attention control (Itti and Koch 2001) onto a simple nonlinear dynamical system (three coupled differential–delay equations representing PAM). Quasiperiodic perceptual reversals are induced by attention satiation (fatigue) with a perception bias which balances the relative duration, i.e. the relative preference of the different percepts. Memory effects are introduced by allowing for the adaptation of the originally constant perception bias parameter. Hurst parameter values of perception reversal time series exhibit significant long range correlations (H > 0.5) in the simulations when coupling the bias parameter to the perception state, i.e. allowing for memory and learning. The coupled attention–perception dynamics reproduces the experimentally observed Gamma-distribution of the reversal time statistics. Mean reversal times of typically 3 – 5 s as reported in the literature, are correctly predicted if delay T is associated with the latency of 30 - 40 ms between stimulus onset and V1/V2 visual cortex response. Numerically determined perceptual transition times of 3 – 5 T are in reasonable agreement with stimulus – conscious perception delay of 150 – 200 ms. The rescaled absolute value of the attention parameter exhibits good agreement with the dynamics of the eye blink rate as reported by Ito et.al. (2003).