Dear Jason,
see the help text in spm_regions.m:
what is displayed is the first eigenvariate of the filtered and adjusted
response in all suprathreshold voxels within a specified VOI. In
particular, the filtering consists of a temporal high pass filter and
whitening (non-sphericity correction), see l. 134-135, while the
adjustment is made by specifying a bi-partition of the design matrix
through an F-contrast, see l. 151.
Which F-contrast did you use to adjust the data? Does the null space of
that contrast contain the offset term (effectively mean-centering the
data)? I currently manage to reproduce what you observe only if I don't
adjust the data with respect to its mean.
Best regards,
Guillaume.
Jason Stretton wrote:
> can anyone explain what the graph represents when clicking the
> eigenvariate button? I'm particularly confused by the first and last
> response being substantially higher than the rest of the time-series?
>
> Thanks
>
> Jason
--
Guillaume Flandin, PhD
Wellcome Trust Centre for Neuroimaging
University College London
12 Queen Square
London WC1N 3BG
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