Determinants of resting regional cerebral blood flow in normal subjects

Study of brain function via cerebral blood flow and metabolism measurements is believed to be of considerable significance in psychiatry. The present study examined the factors that determined patterns of regional cerebral blood flow (CBF) in 140 physically and mentally healthy, drug-free volunteers under resting conditions. Age, sex, and end-tidal CO2 levels were identified as the most powerful determinants of CBF, in that order. Age-related CBF reduction was found to be most marked in the frontal region. Women had higher CBF than men, and the difference was most obvious in the frontal region. The correlations between CO2 and CBF showed less striking, but significant, regional variations. Hematocrit was found to exert only minimal influence in the control of resting CBF.