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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Veröffentlicht in:	Journal of cerebral blood flow and metabolism Jg. 30; H. 1; S. 2 - 14
Hauptverfasser:	Paulson, Olaf B, Hasselbalch, Steen G, Rostrup, Egill, Knudsen, Gitte Moos, Pelligrino, Dale
Format:	Journal Article
Sprache:	Englisch
Veröffentlicht:	London, England SAGE Publications 01.01.2010 Nature Publishing Group Sage Publications Ltd
Schlagworte:	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
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Zusammenfassung:	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.
Bibliographie:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 14 ObjectType-Article-2 ObjectType-Feature-1 content type line 23 ObjectType-Review-3
ISSN:	0271-678X 1559-7016 1559-7016
DOI:	10.1038/jcbfm.2009.188