title: A unified account of tilt illusions, association fields, and contour detection based on elastica.
abstract: As expressed in the Gestalt law of good continuation, human perception tends to associate stimuli that form smooth continuations. Contextual modulation in primary visual cortex, in the form of association fields, is believed to play an important role in this process. Yet a unified and principled account of the good continuation law on the neural level is lacking. In this study we introduce a population model of primary visual cortex. Its contextual interactions depend on the elastica curvature energy of the smoothest contour connecting oriented bars. As expected, this model leads to association fields consistent with data. However, in addition the model displays tilt-illusions for stimulus configurations with grating and single bars that closely match psychophysics. Furthermore, the model explains not only pop-out of contours amid a variety of backgrounds, but also pop-out of single targets amid a uniform background. We thus propose that elastica is a unifying principle of the visual cortical network.
authors.affiliation: Institute for Adaptive and Neural Computation, School of Informatics, University of Edinburgh, 10 Crichton Street, Edinburgh EH8 9AB, UK; Bernstein Center Freiburg, Faculty of Biology, University of Freiburg, Hansastr. 9a, 79104 Freiburg, Germany. Electronic address: s.keemink@sms.ed.ac.uk.
authors.forename: Sander W
authors.initials: SW
authors.lastname: Keemink
authors.affiliation: Institute for Adaptive and Neural Computation, School of Informatics, University of Edinburgh, 10 Crichton Street, Edinburgh EH8 9AB, UK.
authors.forename: Mark C W
authors.initials: MCW
authors.lastname: van Rossum
mesh_terms: D005556:Form Perception / Q000502:physiology*; D005863:Gestalt Theory; D006801:Humans; D008959:Models, Neurological; D008962:Models, Theoretical; D009903:Optical Illusions / Q000502:physiology*; D010775:Photic Stimulation; D011601:Psychophysics; D014796:Visual Perception / Q000502:physiology*
keywords: Association fields; Contextual interactions; Elastica; Gestalt; Smoothness; Tilt illusion