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Variability in FMRI: A Re-Examination of Intersession Differences
FMRIB Technical Report TR04SS1
(A related paper has been accepted by
Human Brain Mapping)
S.M. Smith, C.F. Beckmann, N. Ramnani, M.W. Woolrich,
P.R. Bannister, M. Jenkinson, P.M. Matthews, D.J. McGonigle
Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB),
Department of Clinical Neurology, University of Oxford, John Radcliffe Hospital,
Headley Way, Headington, Oxford, UK
(DM is at Laboratoire de Neurosciences Cognitives et Imagerie
Cérébrale, Hôpital de la Salpêtrière, CNRS UPR 640 - LENA, Paris)
Abstract:
We revisit the McGonigle et al (2000) paper on
intersession variability, showing that, contrary to one popular
interpretation of the original paper, intersession variability is not
necessarily high. We also highlight how evaluating variability on the
basis of thresholded single-session images alone can be misleading.
Finally, we show that the use of different first-level pre-processing,
time-series statistics and registration analysis methodologies can
give significantly different intersession analysis results.
Keywords: FMRI, session variability, reproducibility, longitudinal studies
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