Cerebral Blood Flow Response to Functional Activation

Cerebral blood flow (CBF) and cerebral metabolic rate are normally coupled, that is an increase in metabolic demand will lead to an increase in flow. However, during functional activation, CBF and glucose metabolism remain coupled as they increase in proportion, whereas oxygen metabolism only increa...

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Published in:Journal of cerebral blood flow and metabolism Vol. 30; no. 1; pp. 2 - 14
Main Authors: Paulson, Olaf B, Hasselbalch, Steen G, Rostrup, Egill, Knudsen, Gitte Moos, Pelligrino, Dale
Format: Journal Article
Language:English
Published: London, England SAGE Publications 01.01.2010
Nature Publishing Group
Sage Publications Ltd
Subjects:
Animals
Arterioles - physiology
Astrocytes - physiology
Biological and medical sciences
Brain Chemistry - physiology
Capillaries - physiology
Cerebrovascular Circulation - physiology
Glucose - metabolism
Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy
Humans
Magnetic Resonance Imaging
Medical sciences
Nervous system (semeiology, syndromes)
Neurology
Oxygen - blood
Oxygen Consumption - physiology
Review
Vascular diseases and vascular malformations of the nervous system
CBF (cerebral blood flow)
neurovascular coupling
glucose brain metabolism
oxidative brain metabolism
BOLD (blood oxygenation level dependent)
fMRI (functional magnetic resonance imaging)
Nervous system diseases
Glucose
Metabolism
Nuclear magnetic resonance imaging
Cerebral disorder
Blood flow
Encephalon
Central nervous system disease
Oxygenation
Cerebrovascular disease
Functional imaging
ISSN:0271-678X, 1559-7016, 1559-7016
Online Access:Get full text
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Summary:Cerebral blood flow (CBF) and cerebral metabolic rate are normally coupled, that is an increase in metabolic demand will lead to an increase in flow. However, during functional activation, CBF and glucose metabolism remain coupled as they increase in proportion, whereas oxygen metabolism only increases to a minor degree—the so-called uncoupling of CBF and oxidative metabolism. Several studies have dealt with these issues, and theories have been forwarded regarding the underlying mechanisms. Some reports have speculated about the existence of a potentially deficient oxygen supply to the tissue most distant from the capillaries, whereas other studies point to a shift toward a higher degree of non-oxidative glucose consumption during activation. In this review, we argue that the key mechanism responsible for the regional CBF (rCBF) increase during functional activation is a tight coupling between rCBF and glucose metabolism. We assert that uncoupling of rCBF and oxidative metabolism is a consequence of a less pronounced increase in oxygen consumption. On the basis of earlier studies, we take into consideration the functional recruitment of capillaries and attempt to accommodate the cerebral tissue's increased demand for glucose supply during neural activation with recent evidence supporting a key function for astrocytes in rCBF regulation.
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ISSN:0271-678X
1559-7016
1559-7016
DOI:10.1038/jcbfm.2009.188