Regional differences in the coupling between resting cerebral blood flow and metabolism may indicate action preparedness as a default state

Ruben C. Gur, John D Ragland, Martin Reivich, Joel H. Greenberg, Abass Alavi, Raquel E. Gur

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

Although most functional neuroimaging studies examine task effects, interest intensifies in the "default" resting brain. Resting conditions show consistent regional activity, yet oxygen extraction fraction constancy across regions. We compared resting cerebral metabolic rates of glucose (CMRgl) measured with 18F-labeled 2-fluoro-2-deoxy-D-glucose to cerebral blood flow (CBF) 15O-H2O measures, using the same positron emission tomography scanner in 2 samples (n = 60 and 30) of healthy right-handed adults. Region to whole-brain ratios were calculated for 35 standard regions of interest, and compared between CBF and CMRgl to determine perfusion relative to metabolism. Primary visual and auditory areas showed coupling between CBF and CMRgl, limbic and subcortical regions - basal ganglia, thalamus and posterior fossa structures - were hyperperfused, whereas association cortices were hypoperfused. Hyperperfusion was higher in left than right hemisphere for most cortical and subcallosal limbic regions, but symmetric in cingulate, basal ganglia and somatomotor regions. Hyperperfused regions are perhaps those where activation is anticipated at short notice, whereas downstream cortical modulatory regions have longer "lead times" for deployment. The novel observation of systematic uncoupling of CBF and CMRgl may help elucidate the potential biological significance of the "default" resting state. Whether greater left hemispheric hyperperfusion reflects lateral dominance needs further examination.

Original languageEnglish (US)
Pages (from-to)375-382
Number of pages8
JournalCerebral Cortex
Volume19
Issue number2
DOIs
StatePublished - Feb 2009

Keywords

  • Functional neuroimaging
  • Metabolic coupling
  • Resting brain

ASJC Scopus subject areas

  • Cognitive Neuroscience
  • Cellular and Molecular Neuroscience

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