The Global Signal and Its Role in Functional MRI

COEX 

The global signal is widely used as a regressor or normalization factor for removing the effects of global variations in the analysis of functional magnetic resonance imaging (fMRI) experiments. However, there continues to be considerable controversy regarding its use and interpretation. In this talk, I will review the basic properties of the global signal and describe the various ways that it has been used for the analysis of both task-related and resting-state fMRI data. I will also discuss the sources of information that are embedded in the global signal and touch upon emerging views of its role in the analysis of fMRI studies.