Calibrated fMRI reveals altered neurovascular coupling with age during a cognitive stroop task

Introduction: Calibrated fMRI is a technique that allows quantitative estimates of the relative changes in cerebral metabolic rate of oxygen (ΔCMRO2) and cerebral blood flow (ΔCBF) that accompany neural activation, thus providing a way to investigate the coupling between neural and vascular activity in the human brain. In this study we consider differences in neurovascular coupling between a young and a healthy old group during a cognitive Stroop task. Previous work using the Stroop task has shown increased Blood-Oxygenation-Level-Dependent (BOLD) response with increasing age in the frontal cortex, attributed to increased neural processing in this region due to impaired inhibition. However, it is not clear whether it is the neuronal response or vascular confounders that drive these differences, which the present study aims to address.