Maria Guidi1, Laurentius Huber2, Leonie Lampe1, and Harald E. Möller1
Cortical layer-dependent fMRI can investigate effective connectivity of the brain. However, in order to obtain layer-dependent activity information, the unspecific fMRI sensitivity to draining veins must be accounted for, e.g., with calibrated BOLD methods. Regional variations of resting-state fMRI signal fluctuations have been suggested to resemble features of baseline physiology, such as venous blood volume and vascular reactivity. In this study, we investigate the possibility to use resting-state signal fluctuations to normalize/calibrate layer-dependent fMRI task-responses. In calibration studies with induced hypercapnia, we validate the new approach to obtain cortical profiles of vascular reactivity by comparisons with the established M-value.
