Simultaneous oxygenation and perfbsion imaging study of functional activity in primary visual cortex at different visual stimulation frequency: Quantitative correlation between BOLD and CBF changes

A relationship between regional cerebral blood flow (CBF) and blood oxygenation level dependent (BOLD) changes in the primary visual cortex (V1) at varied visual stimulation fre quency has been examined quantitatively using the multislice FAIR technique. A linear correlation in the common activation areas between functional BOLD and CBF maps was observed. This supports the hypothesis that the task-stimulated BOLD changes in microvasculature are correlated with the CBF changes that presumably reflect the degree of neuronal ac tivity. The linear correlation coefficients for intrasubject com parisons are more significant than those for intersubject com parisons. This suggests that using intrasubject comparisons for quantitative studies of neuronal activity related to different task stimuli and task performances should be more reliable than using intersubject comparisons.