title: Shape processing area LO and illusory contours.
abstract: Recent functional MRI has demonstrated that illusory contours can activate the primary visual cortex. Our investigation sought to demonstrate whether this correlation reflects computations performed in the primary visual cortex or feedback effects from shape processing area LO. We explored this in a patient who has a bilateral lesion to LO, but a functionally spared V1. Our data indicate that illusory contours are unable to influence behaviour without visual area LO. Whilst we would not claim that our data provide evidence for the 'cognitive' nature of illusory contours, they certainly suggest that illusory contours are dependent upon the computations involved in extracting shape representations in LO. Our data highlight the importance of neuropsychological research in interpreting the role of feedforward and feedback effects in the generation of visual illusions.
authors.affiliation: Department of Psychology, Science Site, Durham University, South Road, Durham DH1 3LE, UK.
authors.forename: Lee H
authors.initials: LH
authors.lastname: de-Wit
authors.forename: Robert W
authors.initials: RW
authors.lastname: Kentridge
authors.forename: A David
authors.initials: AD
authors.lastname: Milner
mesh_terms: D000377:Agnosia / Q000503:physiopathology / Q000523:psychology*; D003463:Cues; D025461:Feedback, Physiological; D005260:Female; D005556:Form Perception / Q000502:physiology*; D006801:Humans; D009903:Optical Illusions / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D012399:Rotation; D014793:Visual Cortex / Q000502:physiology*