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Leenders KL, Perani D, Lammertsma AA, et alCerebral blood flow, blood volume and oxygen utilization: normal values and effect of age. Brain 113:27-47

London School of Hygiene and Tropical Medicine, Londinium, England, United Kingdom
Brain (Impact Factor: 10.23). 03/1990; 113 ( Pt 1)(1):27-47. DOI: 10.1093/brain/113.1.27
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ABSTRACT Regional cerebral blood flow (CBF), oxygen extraction ratio (OER), oxygen utilization (CMRO2) and blood volume (CBV) were measured in a group of 34 healthy volunteers (age range 22-82 yrs) using the 15O steady-state inhalation method and positron emission tomography. Between subjects CBF correlated positively with CMRO2, although the interindividual variability of the measured values was large. OER was not dependent on CMRO2, but highly negatively correlated with CBF. CBV correlated positively with CBF. When considering the values of all the regions of interest within a single subject, a strict coupling between CMRO2 and CBF, and between CBF and CBV was found, while OER was constant and independent of CBF and CMRO2. In 'pure' grey and white matter regions CMRO2, CBF and CBV decreased with age approximately 0.50% per year. In other regions the decline was less evident, most likely due to partial volume effects. OER did not change or showed a slight increase with age (maximum in the grey matter region 0.35%/yr). The results suggest diminished neuronal firing or decreased dendritic synaptic density with age.

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    • "Due to the nature of our study, a dichotomous comparison between young and old subject-groups, we could not evaluate the pattern of age-related decreases in oxygen metabolism. Some earlier studies have found this decrease to be linear and starting at a young age [Leenders et al., 1990; Marchal et al., 1992] while others found the oxygen metabolism to remain stable up to 40 years of age, after which point it substantially declined [Devous, Sr. et al., 1986]. Future studies should include subjects across a wide range of ages to investigate this property. "
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    • "Accurate exploration of our environment requires that we know both the spatial location and the relative timing of sensory information. Such abilities decline with age (Evans et al., 1992; Stevens and Choo, 1996) and reflect the overall physiological, structural, and metabolic changes that occur in the elderly (Raz et al., 2005; Terry et al., 1987; Leenders et al., 1990). Therefore in recent years there has been much interest in a number of reports showing that training can improve perceptual abilities even in adults (Gilbert et al., 2001; Seitz and Dinse, 2007; Citri and Malenka, 2008). "
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    • "comparison, the brain is about 5% blood by volume (Leenders et al., 1990). Consequently, much more activity in a liver voxel is contained in the blood compartment. "
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