Table 2.

Nuisance regressors used to denoise fMRI data

Procedure/regressor	# regressors	Comment
Motion parameters
Realignment estimates (MOT)	6
Realignment estimate derivatives (MOT′)	6
Nuisance signals
Mean white matter signal (eroded 4x) (WM)	1
Mean ventricle signal (eroded 2x) (CSF)	1
PCA of all eroded white matter and ventricle signals	5
Local white matter	Not performed	Mean and PCA signals should better reflect global signals
Physiological models
RETROICOR (Glover et al., 2000)	8
RVT (Birn et al., 2006)	5
RVT*RRF (Birn et al., 2008)	5
RV (Chang et al., 2009)	3
RV*RRF (Chang et al., 2009)	3
Gray matter signals
ICA of all gray matter signals	Not performed	Studied in the HCP dataset, which has undergone FIX-ICA, see Video 5
Global signal (GS)	1
PCA of all gray matter signals	Not performed	Correlates with global signal at nearly r = 1 (Carbonell et al., 2011)
Combinations of Figure 7
MOT+MOT′+WM+CSF (+RVT+RVT*RRF) (+GS)