title: Ambiguous results in functional neuroimaging data analysis due to covariate correlation.
abstract: In this note we draw attention to a source of potential ambiguity in functional neuroimaging results when data analysis is based on the resolution of a linear model. This ambiguity arises whenever there exists correlation between the model covariates. A single-subject PET activation experiment helps to illustrate to what extent correlation can affect statistical results interpretation, possibly leading to misinterpretation of part of the activation pattern. This note is intended to clarify this point and to suggest the use of a simple and well-known procedure to deal with these situations. In the Appendix, we suggest a convenient mathematical formulation for statistical tests particularly useful in such cases.
authors.affiliation: Service Hospitalier Frédéric Joliot, Commissariat à l'Energie Atomique, Orsay Cedex, 91401, France.
authors.forename: A
authors.initials: A
authors.lastname: Andrade
authors.forename: A L
authors.initials: AL
authors.lastname: Paradis
authors.forename: S
authors.initials: S
authors.lastname: Rouquette
authors.forename: J B
authors.initials: JB
authors.lastname: Poline
mesh_terms: D001921:Brain / Q000000981:diagnostic imaging / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016018:Least-Squares Analysis; D008959:Models, Neurological; D015233:Models, Statistical; D010104:Oxygen Radioisotopes / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D014055:Tomography, Emission-Computed / Q000379:methods*; D014867:Water
chemical_list: D010104:Oxygen Radioisotopes; D014867:Water