Trouble at Rest: How Correlation Patterns and Group Differences Become Distorted After Global Signal Regression

Resting-state functional magnetic resonance imaging (RS-FMRI) holds the promise of revealing brain functional connectivity without requiring specific tasks targeting particular brain systems. RS-FMRI is being used to find differences between populations even when a specific candidate target for traditional inferences is lacking. However, the problem with RS-FMRI is a lacking definition of what constitutes noise and signal. RS-FMRI is easy to acquire but is not easy to analyze or draw inferences from. In this commentary we discuss a problem that is still treated lightly despite its significant impact on RS-FMRI inferences; global signal regression (GSReg), the practice of projecting out signal averaged over the…

• WT
  Wellcome Trust
• NI
  National Institutes of Health
• NI
  National Institute of Mental Health
• NI
  National Institute of Neurological Disorders and Stroke