Oxygen Consumption and Blood Flow Coupling in Human Motor Cortex during Intense Finger Tapping: Implication for a Role of Lactate

• Published in: Journal of cerebral blood flow and metabolism Vol. 32; no. 10; pp. 1859 - 1868
• Main Authors: Vafaee, Manouchehr S, Vang, Kim, Bergersen, Linda H, Gjedde, Albert
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01-10-2012; Nature Publishing Group; Sage Publications Ltd
• Subjects: Adult; Apposition; Biological and medical sciences; Blood Gas Analysis; Brain; Cerebellum; Cerebral blood flow; Cerebral circulation. Blood-brain barrier. Choroid plexus. Cerebrospinal fluid. Circumventricular organ. Meninges; Cerebrovascular Circulation; Cortex; Cortex (motor); Energy Metabolism; Female; Finger; Fingers - physiology; Fundamental and applied biological sciences. Psychology; Glucose; Glucose - metabolism; Glycolysis; Hand; Humans; Lactic acid; Lactic Acid - metabolism; Male; Medical sciences; Metabolic rate; Metabolites; Motor Activity; Motor Cortex - blood supply; Motor Cortex - diagnostic imaging; Motor Cortex - metabolism; Motor task performance; Neurology; Original; Oxygen Consumption; Physical training; Positron emission tomography; supplementary motor area; Vascular diseases and vascular malformations of the nervous system; Vertebrates: nervous system and sense organs; Young Adult; neurovascular coupling; lactate; positron emission tomography; energy metabolism; Human; Energy metabolism; Nervous system diseases; Finger; Oxygen consumption; Cerebral disorder; Blood flow; Lactates; Motor cortex; Central nervous system disease; Lactic acid; Positron emission tomography; Cerebrovascular disease; Emission tomography
• ISSN: 0271-678X; 1559-7016
• DOI: 10.1038/jcbfm.2012.89

Rates of cerebral blood flow (CBF) and glucose consumption (CMRglc) rise in cerebral cortex during continuous stimulation, while the oxygen-glucose index (OGI) declines as an index of mismatched coupling of oxygen consumption (cerebral metabolic rate of oxygen—CMRO2) to CBF and CMRglc. To test whether the mismatch reflects a specific role of aerobic glycolysis during functional brain activation, we determined CBF and CMRO2 with positron emission tomography (PET) when 12 healthy volunteers executed finger-to-thumb apposition of the right hand. Movements began 1, 10, or 20 minutes before administration of the radiotracers. In primary and supplementary motor cortices and cerebellum, CBF had increased at 1 minute of exercise and remained elevated for the duration of the 20-minute session. In contrast, the CMRO2 numerically had increased insignificantly in left M1 and supplementary motor area at 1 minute, but had declined significantly at 10 minutes, returning to baseline at 20 minutes. As measures of CMRglc are impossible during short-term activations, we used measurements of CBF as indices of CMRglc. The decline of CMRO2 at 10 minutes paralleled a calculated decrease of OGI at this time. The implied generation of lactate in the tissue suggested an important hypothetical role of the metabolite as regulator of CBF during activation.