Spatial relationship between neuronal activity and BOLD functional MRI.
Despite the ubiquitous use of functional magnetic resonance imaging (fMRI), the extent to which the magnitude and spatial scale of the fMRI signal correlates with neuronal activity is poorly understood. In this study, we directly compared single and multiunit neuronal activity with blood oxygenation level-dependent (BOLD) fMRI responses across a large area of the cat area 18. Our data suggest that at the scale of several millimeters, the BOLD contrast correlates linearly with the underlying neuronal activity. At the level of individual electrode recording sites, however, the correlation between the two signals varied substantially. We conclude from our study that T(2)*-based positive BOLD signals are a robust predictor for neuronal activity only at supra-millimeter spatial scales.
Center for Magnetic Resonance Research, University of Minnesota Medical School, Minneapolis, MN 55455, USA. dskim@bu.edu
Dae-Shik
DS
Kim
Itamar
I
Ronen
Cheryl
C
Olman
Seong-Gi
SG
Kim
Kamil
K
Ugurbil
Louis J
LJ
Toth
D000818:Animals; D001921:Brain / Q000166:cytology / Q000502:physiology*; D002415:Cats; D002540:Cerebral Cortex / Q000166:cytology / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology; D004567:Electrodes, Implanted; D008279:Magnetic Resonance Imaging; D009474:Neurons / Q000502:physiology*; D010100:Oxygen / Q000097:blood*; D010775:Photic Stimulation; D014793:Visual Cortex / Q000166:cytology / Q000502:physiology
D010100:Oxygen