Cerebral metabolic relationships for selected brain regions in healthy adults.

The local cerebral metabolic rate for glucose was determined in 26 regions of the brain in 31 healthy subjects who underwent resting fluorodeoxyglucose positron emission tomography. Intercorrelations among the 26 regional measures were accepted as reliable at p less than 0.01 (r greater than 0.45), uncorrected for the number of measures. From the matrix two apparently separate functional metabolic systems were identified: (1) a superior system involving the superior and middle frontal gyri, the inferior parietal lobule, and the occipital cortex; and (2) an inferior system involving the inferior frontal, Broca's, and posterior temporal regions. Evidence is presented to suggest that the superior system is involved in visual processing, memory recognition, and decision making, while the inferior system seems to at least participate in language-related functions.