Dear all.
I have some questions about a band pass filtering method (LPF and HPF) in spm99.
Different from spm96, it seems that HPF is not explicitly modeled in design matrix in spm99.
Seeing spm_filter.m and spm_spm.m, HPF is applied to raw data and each column of design matrix
separately before GLM estimation.
Y= LPF*Y
Y=Y-HPF*(HPF'*Y)
Here, Y is raw data or one column of design matrix.
These processes are equivalent to that of spm96? (e.g. Why does the decrease of d.f.
happen due to HPF nevertheless HPF is not explicitly modeled? V matrix (i.e. xX.V)
contain the information about HPF? )
To test effect of HPF, I have to specified the design matrix as containing
cosine basis function for HPF using user-specified regressors?
Please tell me reference or text about this method,
that is, band pass filtering using the projector matrix
and its statistical inference.
Thank you for your help,
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Takanori Kochiyama
Graduate School of Human and Environmental Studies
Kyoto University
E-mail:[log in to unmask]
Tel:+81 75 753 7862
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