The perils of global signal regression for group comparisons: a case study of Autism Spectrum Disorders.

ABSTRACT: We have previously argued from a theoretical basis that the standard practice of regression of the Global Signal from the fMRI time series in functional connectivity studies is ill advised, particularly when comparing groups of participants. Here, we demonstrate in resting-state data from participants with an Autism Spectrum Disorder and matched controls that these concerns are also well founded in real data. Using the prior theoretical work to formulate predictions, we show: (1) rather than simply altering the mean or range of correlation values amongst pairs of brain regions, Global Signal Regression systematically alters the rank ordering of values in addition to introducing negative values, (2) it leads to a reversal in the direction of group correlation differences relative to other p

SUBMITTER: Gotts SJ 

PROVIDER: S-EPMC3709423 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature