Intersubject variability of functional areas in the human visual cortex

Mohammed K. Hasnain, Peter T. Fox, Marty G. Woldorff

Research output: Contribution to journalArticlepeer-review

125 Scopus citations


Intersubject variability of striate and extrastriate areas was mapped by conjoined use of positron emission tomography (PET) and magnetic resonance imaging (MRI). We used two dynamic bowtie-shaped random-dot patterns centered symmetrically around the vertical- and horizontal-meridian, respectively, presented during sequential PET scans in 11 subjects. Control condition was simple fixation on a central dot in absence of a surrounding random dot pattern. V1, V2, VP, V3, V3a, V4, V5, and 'wordform' areas were identified. After spatial normalization to Talairach atlas space, mean locations and standard deviations about these mean locations for x-, y-, and z-axes were calculated for each area in both hemispheres and compared for differences. The mean standard deviation for all axes across all areas tested was found to be small (4.9 mm). No significant differences were found in the mean standard deviations for the x-, y-, and z-axes in the left hemisphere vs. their counterparts in the right hemisphere. However, when mean standard deviations in both hemispheres were polled together by axis, the mean standard deviation for the y-axis (5.3 mm) was found to be significantly different from the mean standard deviation for the x-axis (4.3 mm). Furthermore, in the left hemisphere, the mean standard deviation for the z-axis (5.7 mm) was significantly greater than the mean standard deviation for the x-axis (3.9 mm). The values reported in this study for mean location and standard deviation of visual areas can be used to establish confidence intervals for distinguishing normal variations from pathology and consequent brain reorganization.

Original languageEnglish (US)
Pages (from-to)301-315
Number of pages15
JournalHuman Brain Mapping
Issue number4
StatePublished - 1998


  • Brain mapping
  • Extrastriate cortex
  • Positron emission tomography
  • Retinotopy
  • Striate cortex (V1)
  • V2
  • V3
  • V3a
  • V4
  • V5
  • VP

ASJC Scopus subject areas

  • Anatomy
  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging
  • Neurology
  • Clinical Neurology


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