Localizing sites of activation in primary visual cortex using visual-evoked potentials and functional magnetic resonance imaging

Suzanne Baker, Heidi Baseler, Stanley Klein, Thom Carney

Research output: Contribution to journalArticlepeer-review


This study compared retinotopic map identification in primary visual cortex (V1) using: (i) functional magnetic resonance imaging (fMRI) and (ii) visual evoked potentials (VEPs) coupled with dipole source localization (DSL). A multielectrode array was used to record VEPs while subjects viewed a flickering dartboard pattern modulated by a 16-bit m-sequence. The stimulus preferentially activates V1. Using a common time function DSL algorithm, the primary source of each stimulus patch was found independent of the fMRI. The VEP/DSL and fMRI localization data for each subject were aligned by a rigid translation and rotation. The average distance between VEP and corresponding fMRI sources was 10.8 mm +/- 3.8 mm. To assess the significance of the results, fMRI and DSL solutions were scrambled so the comparisons were no longer for corresponding patches. The average distance between the noncorresponding data sets was 17.2 mm for 50 million scrambles. The probability of the scrambled data yielding a better fit than the real data was p
Original languageEnglish
Pages (from-to)404-15
Number of pages12
JournalJournal of clinical neurophysiology : official publication of the American Electroencephalographic Society
Issue number5
Publication statusPublished - Oct 2006


  • Brain Mapping
  • Evoked Potentials, Visual
  • Functional Laterality
  • Humans
  • Image Processing, Computer-Assisted
  • Imaging, Three-Dimensional
  • Magnetic Resonance Imaging
  • Oxygen
  • Pattern Recognition, Visual
  • Photic Stimulation
  • Visual Cortex

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