title: Visibility reflects dynamic changes of effective connectivity between V1 and fusiform cortex.
abstract: Identifying the neural basis of visibility is central to understanding conscious visual perception. Visibility of basic features such as brightness is often thought to reflect activity in just early visual cortex. But here we show under metacontrast masking that fMRI activity in stimulus-driven areas of early visual cortex did not reflect parametric changes in the visibility of a brightness stimulus. The psychometric visibility function was instead correlated with activity in later visual regions plus parieto-frontal areas, and surprisingly, in representations of the unstimulated stimulus surround for primary visual cortex. Critically, decreased stimulus visibility was associated with a regionally-specific decoupling between early visual cortex and higher visual areas. This provides evidence that dynamic changes in effective connectivity can closely reflect visual perception.
authors.affiliation: Institute of Cognitive Neuroscience, University College London, Alexandra House, 17 Queen Square, London WC1N 3AR, United Kingdom. haynes@fil.ion.ucl.ac.uk
authors.forename: John-Dylan
authors.initials: JD
authors.lastname: Haynes
authors.forename: Jon
authors.initials: J
authors.lastname: Driver
authors.forename: Geraint
authors.initials: G
authors.lastname: Rees
mesh_terms: D000328:Adult; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D009434:Neural Pathways / Q000502:physiology; D010775:Photic Stimulation / Q000379:methods*; D011597:Psychomotor Performance / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*