Inertia and memory in ambiguous visual perception

Abstract

Perceptual multistability during ambiguous visual perception is an important clue to neural dynamics. We examined perceptual switching during ambiguous depth perception using a Necker cube stimulus, and also during binocular rivalry. Analysis of perceptual switching time series using variance-sample size analysis, spectral analysis and time series shuffling shows that switching times behave as a 1/f noise and possess very long range correlations. The long memory feature contrasts sharply with the traditional satiation models of multistability, where the memory is not incorporated, as well as with recently published models of multistability and neural processing, where memory is excluded. On the other hand, the long memory feature favors the concept of "dynamic core" or coalition of neurons, where neurons form transient coalitions. Perceptual switching then corresponds to replacement of one coalition of neurons by another. The inertia and memory measures the stability of a coalition: a strong and stable coalition has to be won over by another similarly strong and stable coalition, resulting in long switching times. The complicated transient dynamics of competing coalitions of neurons may be addressable using a combination of functional imaging, measurement of frequency-tagged magnetoencephalography and frequency-tagged encephalography, simultaneous recordings of groups of neurons in many areas of the brain, and concepts from statistical mechanics and nonlinear dynamics theory.

A nonlinear dynamics model for simulating long range correlations of cognitive bistability

“…These authors use an additive stimulus and nonlinearity only present in the coupling between the alternative percepts. Within the present model, the experimentally observed difference of the perceptual duration time statistics between binocular rivalry and perception reversal with regard to the stochastic and deterministic character (Richards et al 1994;Gao et al 2006a) can be explained via different memory time constants of the dynamical attention bias which determines the long range correlations.…”

“…During the recent years, an increasing number of experimental and theoretical results indicate the chaotic and fractal character of brain functioning (Richards et al 1994;Lutzenberger et al 1995;Dafilis et al 2001;Burke and de Paor 2004;Freeman 2000;Gao et al 2006a). This appears not surprising, considering the 10 11 neurons with nonlinear transfer characteristic constituting the brain hardware, each one coupled with 10 3 -10 4 others so that the dynamics of a massive nonlinear delayed feedback system has to be taken into consideration.…”

“…Recently, Gao et al (2006a) presented experimental evidence for the fractal and chaotic character of brain dynamics. It was obtained from analysis of perceptual dwell time series of ambiguous stimuli, such as the Necker cube and binocular rivalry via determination of the self-similarity (Hurst) parameter H (Mandelbrot 1991;Beran 1992).…”

“…From the above given overview, it appears reasonable to assume that both deterministic and stochastic contributions to the cognitive system dynamics have to be considered. The Hurst parameter H as used by Gao et al (2006a) is a convenient parameter to quantify the relative importance of deterministic and stochastic dynamics. For example, H = 0.5 describes a completely stochastic (random walk) system governed by the laws of Brownian motion without any memory effects, whereas a system with H = 1 is completely deterministic and the initial conditions completely determine the future development.…”

“…and stimuli, such as binocular rivalry (Blake and Logothetis 2002), perspective reversal, e.g., with the famous Necker cube (e.g., Orbach et al 1963;Borsellino et al 1972;Gao et al 2006a), and apparent motion displays (Hock et al 1993(Hock et al , 1997. Tristable perception was investigated by Ito et al (2003).…”