Motion or activity: their role in intra- and inter-subject variation in fMRI

Neuroimage. 2005 Jul 1;26(3):960-4. doi: 10.1016/j.neuroimage.2005.02.021. Epub 2005 Mar 29.


Functional MRI (fMRI) carries the potential for non-invasive measurements of brain activity. Typically, what are referred to as activation images are actually thresholded statistical parametric maps. These maps possess large inter-session variability. This is especially problematic when applying fMRI to pre-surgical planning because of a higher requirement for intra-subject precision. The purpose of this study was to investigate the impact of residual movement artefacts on intra-subject and inter-subject variability in the observed fMRI activation. Ten subjects were examined using three different word-generation tasks. Two of the subjects were examined 10 times on 10 different days using the same paradigms. We systematically investigated one approach of correcting for residual movement effects: the inclusion of regressors describing movement-related effects in the design matrix of a General Linear Model (GLM). The data were analysed with and without modeling the residual movement artefacts and the impact on inter-session variance was assessed using F-contrasts. Inclusion of motion parameters in the analysis significantly reduced both the intra-subject as well as the inter-subject-variance.

MeSH terms

  • Adult
  • Artifacts
  • Brain / physiology*
  • Brain Mapping / methods*
  • Data Interpretation, Statistical
  • Humans
  • Linear Models
  • Magnetic Resonance Imaging / statistics & numerical data*
  • Models, Neurological
  • Movement / physiology*
  • Psychomotor Performance / physiology
  • Reproducibility of Results
  • Speech / physiology