Extrastriate loci for the perception of stereo depth and illusory contours: Evidence from fMRI

J. Hirsch, K. Kim, N. Relkin, J. Victor, K. M. Lee, D. R. Moreno, S. Kalik, R. L. DeLaPaz, N. Rubin, R. Shapley

Research output: Contribution to journalArticlepeer-review


Purpose. We have previously demonstrated localized regions in human cortex associated with stereo depth and illusory contours. In this study we aimed to use a high-resolution MRI method for direct visualization of the Stria of Gennari 2 to determine the relationship of these areas to primary visual cortex. Methods. Images were acquired on a GE Signa 1.5T scanner equipped for echoplanar imaging and a resolution of 1.5x1.5mm2. Multiple axial slices were acquired during baseline, visual stimulation, and post stimulation periods. Signal intensities were compared during baseline and stimulation periods to identify "active" voxels. Stimulation conditions included: 1) red-green random spot anaglyphs that produced a stereo-defined square; 2) a random spot pattern with no stereo, 3) four pacman at the corners of a Kanizsa square (illusory contours) and 4) four non-aligned pacmen. Results. The activity elicited by stereo-contours and illusory contours was observed predominately in right occipital cortex. These areas were outside the areas of visual cortex in which the Stria of Gennari was visualized. Conclusion. Extra-striate cortical areas in human brain are active during the perception of stereo depth and illusory contours.

Original languageEnglish (US)
Pages (from-to)S934
JournalInvestigative Ophthalmology and Visual Science
Issue number3
StatePublished - Feb 15 1996

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience


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