title: Sensory dynamics of visual hallucinations in the normal population.
abstract: Hallucinations occur in both normal and clinical populations. Due to their unpredictability and complexity, the mechanisms underlying hallucinations remain largely untested. Here we show that visual hallucinations can be induced in the normal population by visual flicker, limited to an annulus that constricts content complexity to simple moving grey blobs, allowing objective mechanistic investigation. Hallucination strength peaked at ~11 Hz flicker and was dependent on cortical processing. Hallucinated motion speed increased with flicker rate, when mapped onto visual cortex it was independent of eccentricity, underwent local sensory adaptation and showed the same bistable and mnemonic dynamics as sensory perception. A neural field model with motion selectivity provides a mechanism for both hallucinations and perception. Our results demonstrate that hallucinations can be studied objectively, and they share multiple mechanisms with sensory perception. We anticipate that this assay will be critical to test theories of human consciousness and clinical models of hallucination.
authors.affiliation: The School of Psychology, University of New South Wales, Sydney, Australia.
authors.forename: Joel
authors.identifier: 0000-0003-3704-5037
authors.initials: J
authors.lastname: Pearson
authors.affiliation: The School of Psychology, University of New South Wales, Sydney, Australia.
authors.forename: Rocco
authors.initials: R
authors.lastname: Chiou
authors.affiliation: The School of Psychology, University of New South Wales, Sydney, Australia.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Rogers
authors.affiliation: The School of Psychology, University of New South Wales, Sydney, Australia.
authors.forename: Marcus
authors.initials: M
authors.lastname: Wicken
authors.affiliation: Department of Mathematics, University of Pittsburgh, Pittsburgh, United States.
authors.forename: Stewart
authors.initials: S
authors.lastname: Heitmann
authors.affiliation: Department of Mathematics, University of Pittsburgh, Pittsburgh, United States.
authors.forename: Bard
authors.initials: B
authors.lastname: Ermentrout
mesh_terms: D006212:Hallucinations; D006801:Humans; D008959:Models, Neurological; D014793:Visual Cortex / Q000502:physiology*
keywords: binocular rivalry; bistability; flicker; hallucinations; human; illusion; neural field model; neuroscience