TY - JOUR

T1 - Oxygen consumption and blood flow coupling in human motor cortex during intense finger tapping

T2 - implication for a role of lactate

AU - Seyedi Vafaee, Manouchehr

AU - Vang, Kim

AU - Bergersen, Linda H

AU - Gjedde, Albert

PY - 2012/10

Y1 - 2012/10

N2 - Rates of cerebral blood flow (CBF) and glucose consumption (CMR(glc)) 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-CMRO(2)) to CBF and CMR(glc). To test whether the mismatch reflects a specific role of aerobic glycolysis during functional brain activation, we determined CBF and CMRO(2) 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 CMRO(2) 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 CMR(glc) are impossible during short-term activations, we used measurements of CBF as indices of CMR(glc). The decline of CMRO(2) 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.

AB - Rates of cerebral blood flow (CBF) and glucose consumption (CMR(glc)) 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-CMRO(2)) to CBF and CMR(glc). To test whether the mismatch reflects a specific role of aerobic glycolysis during functional brain activation, we determined CBF and CMRO(2) 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 CMRO(2) 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 CMR(glc) are impossible during short-term activations, we used measurements of CBF as indices of CMR(glc). The decline of CMRO(2) 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.

KW - Adult

KW - Blood Gas Analysis

KW - Cerebrovascular Circulation

KW - Energy Metabolism

KW - Female

KW - Fingers

KW - Glucose

KW - Humans

KW - Lactic Acid

KW - Male

KW - Motor Activity

KW - Motor Cortex

KW - Oxygen Consumption

KW - Positron-Emission Tomography

KW - Young Adult

U2 - 10.1038/jcbfm.2012.89

DO - 10.1038/jcbfm.2012.89

M3 - Journal article

C2 - 22781333

VL - 32

SP - 1859

EP - 1868

JO - Journal of Cerebral Blood Flow and Metabolism

JF - Journal of Cerebral Blood Flow and Metabolism

SN - 0271-678X

IS - 10

ER -