Hi Dan,
1) The polort 0 terms that I mentioned are the beta weights for the constant terms in the linear regression. You are probably not even getting them as output (by default, they are not output). Given that, it might be more simple to just say that 'basic' and 'demean' should produce identical results.
2) Using 'demean deriv' will certainly differ. That includes the 6 extra regressors. You should expect that to be different from 'basic' or just 'demean'.
Look at the motion_demean.1D and motion_deriv.1D plots, e.g.
1dplot -sepscl motion_demean.1D &
1dplot -sepscl motion_deriv.1D &
Using "-regress_apply_mot_types demean" will include that first set of 6 time series in the regression. Including 'deriv' means including the second set of 6 as additional regressors. That will change the result.
- rick
