Variability in fMRI: A re‐examination of inter‐session differences

Abstract We revisit a previous study on inter‐session variability (McGonigle et al. 2000 : Neuroimage 11:708–734), showing that contrary to one popular interpretation of the original article, inter‐session variability is not necessarily high. We also highlight how evaluating variability based on thresholded single‐session images alone can be misleading. Finally, we show that the use of different first‐level preprocessing, time‐series statistics, and registration analysis methodologies can give significantly different inter‐session analysis results. Hum. Brain Mapping 24:248–257, 2005. © 2005 Wiley‐Liss, Inc.