REGIONAL CHANGES IN GLUCOSE-METABOLISM DURING BRAIN-DEVELOPMENT FROM THE AGE OF 6 YEARS

Positron emission tomography (PET) with [F-18]fluorodeoxyglucose (FDG) studies of 42 subjects ages 6 to 38 years were analyzed using statist ical parametric mapping to identify age-related changes in regional di stribution of glucose metabolism adjusted for global activity. Whereas adults were normal volunteers, children had idiopathic epilepsy. We s tudied polynomial expansions of age to identify nonlinear effects and found that adjusted glucose metabolism varied very significantly in th e thalamus and the anterior cingulate cortex and to a lesser degree in the basal ganglia, the mesencephalon, and the insular, posterior cing ulate, frontal, and postcentral cortices. Regression plots showed that the best fit was not linear: adjusted glucose metabolism increased ma inly before the age of 25 years and then remained relatively stable. E ffects persisted when anti-epileptic drug intake and sleep during the FDG uptake were considered as confounding covariates. To determine if the metabolic changes observed were not due to the epileptic condition of the children, PET data obtained in adults with temporal lobe epile psy were compared with those in our group of normal adult subjects, re sulting in the absence of mapping in the age-related regions. This stu dy suggests that brain maturation from the age of 6 years gives rise t o a relative increase of synaptic activities in the thalamus, possibly as a consequence of improved corticothalamic connections. Increased m etabolic activity in the anterior cingulate cortex is probably related to these thalamic changes and suggests that the limbic system is invo lved in the processes of brain maturation, (C) 1998 Academic Press.