Orientation-selective adaptation to illusory contours in human visual cortex

Leila Montaser-Kouhsari, Michael S. Landy, David J. Heeger, Jonas Larsson

Research output: Contribution to journalArticlepeer-review


Humans can perceive illusory or subjective contours in the absence of any real physical boundaries. We used an adaptation protocol to look for orientation-selective neural responses to illusory contours defined by phase-shifted abutting line gratings in the human visual cortex. We measured functional magnetic resonance imaging (fMRI) responses to illusory-contour test stimuli after adapting to an illusory-contour adapter stimulus that was oriented parallel or orthogonal to the test stimulus.Wefound orientation-selective adaptation to illusory contours in early (V1 and V2) and higher-tier visual areas (V3, hV4, VO1, V3A/B, V7, LO1, and LO2). That is, fMRI responses were smaller for test stimuli parallel to the adapter than for test stimuli orthogonal to the adapter. In two control experiments using spatially jittered and phase-randomized stimuli, we demonstrated that this adaptation was not just in response to differences in the distribution of spectral power in the stimuli. Orientation-selective adaptation to illusory contours increased from early to higher-tier visual areas. Thus, both early and higher-tier visual areas contain neurons selective for the orientation of this type of illusory contour.

Original languageEnglish (US)
Pages (from-to)2186-2195
Number of pages10
JournalJournal of Neuroscience
Issue number9
StatePublished - Feb 28 2007


  • Adaptation
  • Illusory contours
  • Orientation selectivity
  • Spatial vision
  • Visual cortex
  • fMRI

ASJC Scopus subject areas

  • General Neuroscience


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