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Spatially dissociated flow-metabolism coupling in brain activation.
Manouchehr S Vafaee1, Albert Gjedde
1Center of Functionally Integrative Neuroscience, University of Aarhus, and PET Center, Aarhus University Hospitals, Aarhus, Denmark. manou@pet.auh.dk
Neuroimage
|February 26, 2004
Summary
Functional brain imaging reveals that cerebral blood flow (CBF) and oxygen consumption (CMRO2) do not always rise together during motor tasks. A central command mechanism may regulate CBF in anticipation of movement.
Area of Science:
- Neuroscience
- Functional Brain Imaging
- Cerebrovascular Physiology
Background:
- The coupling between cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), and glucose use (CMRglc) is fundamental to functional brain imaging.
- Conventional models assume tight coupling between CBF and CMRO2 during neural activity.
Purpose of the Study:
- To investigate the spatial relationship between CBF and CMRO2 during motor activity.
- To propose a revision of conventional CBF-CMRO2 coupling models based on observed dissociations.
Main Methods:
- Utilized functional brain imaging techniques to measure CBF and CMRO2 simultaneously during a finger-thumb tapping task.
- Analyzed regional changes in CBF and CMRO2 in motor cortices and the putamen.
Main Results:
- Observed significant increases in both CBF and CMRO2 in the left primary and supplementary motor cortices.
- Found no significant increase in CBF in the right putamen, despite a significant rise in CMRO2.
- Evidence suggests CBF in the putamen increased prior to actual movement, preceding the rise in CMRO2.
Conclusions:
- Spatially dissociated changes in CMRO2 and CBF challenge traditional coupling models.
- A central command mechanism likely regulates putaminal CBF in anticipation of motor activity.
- This anticipatory regulation of CBF may precede the metabolic demand (CMRO2) during movement execution.