fmri_correctmovement

Description

FMRI_CORRECTMOVEMENT Removes motion artifacts from fMRI data via regression. Regresses out motion parameters from the fMRI time series using ordinary least squares (OLS). The motion regressors are z-scored before regression to ensure numerical stability. The residuals represent the data with motion- related variance removed.

Usage

residual = fmri_correctmovement(data, movementfilepath)

Inputs

DATA: fMRI time series, either: vectorized (T x 228453) — scans in rows, voxels in cols volume (91 x 109 x 91 x T)
MOVEMENTFILEPATH: Path to the motion parameter file (string). The file should contain a numeric matrix of size (T x P) where P is the number of motion regressors (typically 6: 3 translations + 3 rotations).

Outputs

RESIDUAL: Motion-corrected data in the same format as DATA input (T x 228453 if vectorized, 91 x 109 x 91 x T if volume).

Examples

residual = fmri_correctmovement(data, 'sub01_motion.txt');
residual = fmri_correctmovement(voldata, '/data/motion/sub04.par');

Notes

Motion parameter files are typically generated by SPM (rp_*.txt) or
FSL (*.par). Both 6-column (rigid body) and extended regressor sets
(e.g., 24-parameter) are accepted.