Spatial specificity of cerebral blood volume-weighted fMRI responses at columnar resolution

Neuroimage. 2005 Aug 15;27(2):416-24. doi: 10.1016/j.neuroimage.2005.04.011.


The spatial specificity of functional magnetic resonance imaging (fMRI) signals to columnar architecture remains uncertain. At columnar resolution, the specificity of intrinsic cerebral blood volume (CBV) response to orientation-selective columns in isoflurane-anesthetized cats was determined for CBV-weighted fMRI signals after injection of iron oxide at a dose of 10 mg Fe/kg. CBV-weighted fMRI data were acquired at 9.4 T with an in-plane resolution of 156 x 156 microm(2) in area 18 during visual stimulation at two orthogonal orientations. A 1-mm-thick imaging slice was selected tangential to the cortical surface. Regions with large CBV changes in response to two orthogonal orientation gratings were highly complementary. Maps of iso-orientation domains in response to these gratings were highly reproducible, suggesting that CBV-weighted fMRI has high sensitivity and specificity. The average distance between iso-orientation domains was 1.37+/- 0.28 mm (n=10 orientations) in an anterior-posterior direction. CBV-weighted fMRI signal change in the iso-orientation domains induced by preferred orientation was 1.69+/- 0.24 (n=10) times larger than that induced by orthogonal orientation. Our data demonstrate that CBV regulates at a submillimeter columnar scale and CBV-weighted fMRI has sufficient specificity to map columnar organization in animals.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Brain Mapping
  • Cats
  • Cerebrovascular Circulation / physiology*
  • Female
  • Ferric Compounds
  • Functional Laterality / physiology
  • Hemodynamics / physiology
  • Magnetic Resonance Imaging*
  • Microspheres
  • Photic Stimulation
  • Reproducibility of Results
  • Space Perception / physiology*
  • Vision, Binocular
  • Visual Cortex / blood supply*
  • Visual Cortex / physiology*


  • Ferric Compounds
  • ferric oxide