Hongjian He1,2, David D. Shin2, Thomas T. Liu2
1Physics Department, Zhejiang University, Hangzhou, Zhejiang, China; 2Center for functional MRI, UC San Diego, La Jolla, CA, United States
Removal of the global mean signal is a common step in the processing of resting-state fMRI data. However, its usage can produce spurious negative correlations. . Here we propose the use of BOLD signal fluctuations in the large draining veins as an alternative to the global mean signal that does not force the existence of negative correlations. We show that signals from two vein regions (sagittal sinus and great vein of Galen) are significantly correlated with the global mean signal and may therefore represent a useful alternative for the analysis of resting-state fMRI studies.