Dear SPM experts,
I have a question as to how to perform detrending and high pass filtering. In our study, participants view movie clips inside the MRI scanner. Due to the complexity of the input, it is not possible to analyse the data using a classical GLM approach modelling the HRF. Instead, we decided to use intersubject correlation (Hasson et al, 2004). This is a model-free approach correlating the voxel-time course for each voxel for each pair of subjects. It requires data to be preprocessed and we performed the pre-processing using the standard preprocessing fmri batch. To make sure that any correlation is not caused by any scanner drift or low frequency noise, we would like to detrend and high pass filter our preprocessed data. I read trough threads related to that issue and if I understand it correctly, any filters are applied during first level modelling. Is there a way to apply filtering outside the GLM? Either in SPM or Matlab itself? If so, how would I do that?
I would be grateful for any inputs or suggestions how to deal with this issue.
Kind regards,
Stef
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Stef Meliss
Doctoral Researcher
Motivation Science Lab
School of Psychology and Clinical Language Sciences
University of Reading
RG6 6AL (Sat Nav: RG6 7BE)
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+44 (0) 118 378 7937
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