Positron emission tomography (PET) studies with 18-fluorodeoxyglucose (18-FDG) to measure brain glucose metabolism in normal-weight individuals reported that exposure to food cues increased metabolic activity in the orbitofrontal cortex, similar to that observed in cocaine-addicted subjects, which was an effect associated with the perception of hunger and the desire for food [ 124].
The randomized study, conducted in 2009, asked 47 participants to undergo positron emission tomography - or PET - scans, which measure brain glucose metabolism, a marker of brain activity.
The development of different diagnostic biomarkers measuring brain Aβ and regional cerebral glucose metabolism by PET, and brain atrophy by MRI as well as CSF biomarkers facilitates the early detection of Alzheimer's disease (Blennow et al., 2010; Frisoni et al., 2010; Nordberg et al., 2010).
We measured regional brain glucose metabolism in 23 healthy subjects when they performed a mathematical task with difficulty controlled to achieve 80% accuracy.
Lowest cerebral glutamate was measured at brain glucose 3-5 mM with a significant increase at brain glucose below 3 mM and above 6 mM.
Several studies using positron emission tomography (PET) to measure brain activity-induced changes in glucose metabolism have concluded an inverse correlation between neural activity and IQ score (or task performance) which is consistent with the neural efficiency hypothesis (Haier et al. 1992, 2000).
Regenold and colleagues [ 40] found that an index of treatment resistance correlated significantly with deep white matter hyperintensity volume, as well as measures of abnormal brain glucose metabolism (sorbitol and fructose) in bipolar patients but not in other patients (i.e, those with schizophrenia and neurologic controls).
Example of a patient showing a linear relationship between blood and brain glucose, measured by cerebral microdialysis (CMD) glucose.
The aim of the present study was to unravel the neural bases of this impairment by mapping in a subgroup of patients correlations between resting-state brain glucose utilization measured by FDG-PET and measures of autobiographical memory (AM) using the TEMPau task which is designed to gauge personal event recollection across five life time periods.
Brain glucose metabolism measured with FDG-PET is highly correlated with postmortem measures of the synaptic structural protein synaptophysin [ 122].
