PowerPoint Presentation

Head Motion in fMRICameron CraddockNathan Kline InstituteChild Mind Institute

Motion Crises in RS-fMRI

Motion Induced Differences in FC

Non-stationary Effects

Motion is Very Consistent

Intersession test-retest reliability = 0.73

Motion ArtifactConsistent bias that increases correlations in lateral regions and decreases correlations in A-P regionsCannot be averaged out with larger samplesHighly reliableReducing head motion decreases test-retest reliability and potentially prediction accuracy

Measuring Motion

Accuracy of motion estimates

Correcting MotionScrubbing remove high motion time pointsIndependent Component Analysis need to select noise componentsNuisance regression movement regression use motion estimates as nuisance covariatesProspective motion correctionTraining

To scrub or not to scrub??

http://imaging.mrc-cbu.cam.ac.uk/imaging/CommonArtefacts

ICAICA decomposes data into statistically independent spatial componentsReconstruct data using only Signal componentsSignal and Noise components need to be distinguished

ICA component SelectionICA FIX classifier model to differentiate good and bad components might require site specific classifiers Salimi-Korshidi 2014AROMA use spatial and temporal motion properties to identify components, retains more DOF than other regressors Pruim 2015Multi-echo ICA uses BOLD signal properties (T2* dependence) to identify signal components Kundu 2015

Nuisance Signal Regression

Prospective Motion Correction

- Track motion using either external system or fMRI images and update slice placement to counteract motion- Tracking system can be bulky require calibration

Training