title: RESCALE: Voxel-specific task-fMRI scaling using resting state fluctuation amplitude.
abstract: The BOLD signal measured in fMRI studies depends not only on neuronal activity, but also on other parameters like tissue vascularization, which may vary between subjects and between brain regions. A correction for variance from vascularization effects can thus lead to improved group statistics by reducing inter-subject variability. The fractional amplitude of low-frequency fluctuations (fALFF) as determined in a resting-state scan has been shown to be dependent on vascularization. Here we present a correction method termed RESCALE (REsting-state based SCALing of parameter Estimates) that uses local information to compute a voxel-wise scaling factor based on the correlation structure of fALFF and task activation parameter estimates from within a cube of 3 × 3 × 3 surrounding that voxel. The scaling method was used on a visuo-motor paradigm and resulted in a consistent increase in t-values in all task-activated cortical regions, with increases in peak t-values of 37.0% in the visual cortex and 12.7% in the left motor cortex. The RESCALE method as proposed herein can be easily applied to all task-based fMRI group studies provided that resting-state data for the same subject group is also acquired.
authors.affiliation: MR Centre of Excellence, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
authors.forename: Klaudius
authors.initials: K
authors.lastname: Kalcher
authors.forename: Roland N
authors.initials: RN
authors.lastname: Boubela
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Huf
authors.forename: Bharat B
authors.initials: BB
authors.lastname: Biswal
authors.forename: Pia
authors.initials: P
authors.lastname: Baldinger
authors.forename: Uta
authors.initials: U
authors.lastname: Sailer
authors.forename: Peter
authors.initials: P
authors.lastname: Filzmoser
authors.forename: Siegfried
authors.initials: S
authors.lastname: Kasper
authors.forename: Claus
authors.initials: C
authors.lastname: Lamm
authors.forename: Rupert
authors.initials: R
authors.lastname: Lanzenberger
authors.forename: Ewald
authors.initials: E
authors.lastname: Moser
authors.forename: Christian
authors.initials: C
authors.lastname: Windischberger
mesh_terms: D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009044:Motor Cortex / Q000502:physiology*; D013647:Task Performance and Analysis; D014793:Visual Cortex / Q000502:physiology*; D055815:Young Adult