Age differences in cerebral blood flow during rest and during mental activation measurements with and without monetary incentive.

This experiment compared the diffuse and regional cerebral blood flow (CBF) during rest and during cognitive activation with and without incentive-induced arousal in young, middle-aged, and older adults. Two normal rest CBF measurements were followed by two mental mathematics activation CBF measurements. For the first activation measurement, half the participants in each age group were offered monetary incentive for correct performance and half the participants received no monetary incentive. All participants were offered monetary incentive on the final activation measurement. Older participants had lower resting blood flow at all detectors, but age-related reductions in blood flow were statistically significant only in anterior and inferior rolandic regions. The effect of monetary incentive was to increase blood flow at the inferior rolandic detector in both hemispheres. The CBF response to cognitive activation and monetary incentive did not differ in the three age groups.