title: A model for the origin and properties of flicker-induced geometric phosphenes.
abstract: We present a model for flicker phosphenes, the spontaneous appearance of geometric patterns in the visual field when a subject is exposed to diffuse flickering light. We suggest that the phenomenon results from interaction of cortical lateral inhibition with resonant periodic stimuli. We find that the best temporal frequency for eliciting phosphenes is a multiple of intrinsic (damped) oscillatory rhythms in the cortex. We show how both the quantitative and qualitative aspects of the patterns change with frequency of stimulation and provide an explanation for these differences. We use Floquet theory combined with the theory of pattern formation to derive the parameter regimes where the phosphenes occur. We use symmetric bifurcation theory to show why low frequency flicker should produce hexagonal patterns while high frequency produces pinwheels, targets, and spirals.
authors: Department of Neuroscience, Brown University, Providence, Rhode Island, United States of America.
authors: Michael
authors: M
authors: Rule
authors: Matthew
authors: M
authors: Stoffregen
authors: Bard
authors: B
authors: Ermentrout
mesh_terms: D019295:Computational Biology; D003198:Computer Simulation; D005425:Flicker Fusion / Q000502:physiology; D006212:Hallucinations / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D008959:Models, Neurological; D009415:Nerve Net / Q000502:physiology; D010719:Phosphenes / Q000502:physiology*; D010775:Photic Stimulation; D014793:Visual Cortex / Q000502:physiology