The Global Signal in fMRI: Nuisance or Information?

By Thomas T. Liu, Alican Nalci, Maryam Falahpour. NeuroImage, 2017

404 citations recorded by the source corpus.

Abstract 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) studies. However, there is considerable controversy over its use because of the potential bias that can be introduced when it is applied to the analysis of both task‐related and resting‐state fMRI studies. In this paper we take a closer look at the global signal, examining in detail the various sources that can contribute to the signal. For the most part, the global signal has been treated as a nuisance term, but there is growing evidence that it may also contain valuable information. We also examine the various ways that the global signal has been used in the analysis of fMRI data, including global signal regression, global signal subtraction, and global signal normalization. Furthermore, we describe new ways for understanding the effects of global signal regression and its relation to the other approaches.

Subfields: Cognitive Neuroscience

View Paper: https://www.semanticscholar.org/paper/d0971e35e7d178eca6856c1340906d5523ef8756

Citations in the corpus

• Aperiodic parameters of the fMRI power spectrum associate with preterm birth and neonatal age (2026, unknown): “…activity is related to the global BOLD signal, which is increasingly being recognized as carrying valuable information about neuronal processes and related to various phenomena such as levels of vigilance and arousal, as well as quasi-periodic patterns of functional activity of the brain 41 .”