The stroboscopic patterns as dissipative structures.

Abstract

Photic stimulation of the human visual system with uniform but intermittent illumination has been recognized for well over a century to give rise to the perception of complex visual patterns and forms. A review of the literature pertaining to these "stroboscopic patterns" is presented, along with a review of theories addressing their origins. The theories range from attributing the patterns to inhomogeneities in the structure of the eye, to the formation of functional domains of neural activity. A novel account of the origins of the patterns is developed in this paper utilizing advances in the neurobiology of information processing and nonlinear dynamics. This view conceptualizes the patterns as examples of "dissipative structures." These dissipative structures are conceived of as self-organizing macrostates of spatio-temporal coherence, widespread among visual cortical neurons. This self-organization is described in terms of nonlinear dynamics, in which sets of attractors emerge within a neural phase space undergoing constant change as the energy contained within successive volleys of stimulation-induced action currents is recursively dissipated by the visual system through cooperative feedback. The trajectories of activity formed by these attractors may reflect the actual form of the perceived patterns themselves and are thought to correspond to some of the reported properties of "linking fields" in the visual cortex.