title: Save the global: global signal connectivity as a tool for studying clinical populations with functional magnetic resonance imaging.
abstract: The global signal is commonly removed from resting-state data, as it was presumed to reflect physiological noise. However, removal of the global signal is now under debate, as this signal may reflect important neuronal components, and its removal may introduce artifacts into the data. Here, we show that the functional connectivity (FC) of the global signal is of functional relevance, as it differentiates between schizophrenia patients and healthy controls during rest. We also demonstrate that other reported findings related to various clinical populations may actually reflect alternations in global signal FC. The evidence of the clinical relevance of the global signal propose its usage as a research tool, and extend previously reported perils of global signal removal in resting-state data of clinical populations.
authors.affiliation: 1 Department of Neurobiology, Weizmann Institute of Science , Rehovot, Israel .
authors.forename: Avital
authors.initials: A
authors.lastname: Hahamy
authors.forename: Vince
authors.initials: V
authors.lastname: Calhoun
authors.forename: Godfrey
authors.initials: G
authors.lastname: Pearlson
authors.forename: Michal
authors.initials: M
authors.lastname: Harel
authors.forename: Nachum
authors.initials: N
authors.lastname: Stern
authors.forename: Fanny
authors.initials: F
authors.lastname: Attar
authors.forename: Rafael
authors.initials: R
authors.lastname: Malach
authors.forename: Roy
authors.initials: R
authors.lastname: Salomon
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D001523:Mental Disorders / Q000503:physiopathology; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology*; D012559:Schizophrenia / Q000503:physiopathology*
keywords: fMRI; functional connectivity; global signal; neuroimaging; resting state; schizophrenia