> I want to take the "raw signal" and then apply detrending (e.g. highpass
> filtering at 128Hz) and temporal autocorrelation correction (e.g. using
> AR(1) model) just as how ordinary SPM procedure does. I searched for a
> script or a thread concerning this issue, but unfortunately I wasn't able to
> find a good advice on this.
> So I came up with one idea which is to use the conventional SPM model
> estimation procedure *without* any regressor specified. This way, the model
> matrix will only include the grand mean (column of ones) for each run. The
> residuals from this estimation should, in theory, give me the "highpass
> filtered" and "temporal autocorrelation corrected" which is further mean
> centered for each run.
sounds good to me - change in spm_defaults the residual number to 'inf'
and in spm_spm comment the bit which actually delete the residuals from
the disk - also in the design matrix you can enter the txt file from the
realignment ; residuals here = data with variance related to motion
removed + filtered as you wanted :-) (note the filtering is high pass /
AR ~ = low pass / drift) -- also the mean will have been removed (that
the contant term in the design matrix)
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