I need to extract the beta weights from a cluster identified with FS-Fast in order to compute percentage signal change.
1) I see a file called beta.nii.gz that appears to have the beta weight information. It has a four dimensional structure and the fourth dimension appears to be the beta weights. Is there an index somewhere as to which beta weight is which? Or if not, how are they organized?
2) In order to extract the cluster, it looks like I would use mri_label2vol to convert cache.th20.neg.sig.ocn.annot into a volume where the voxels are tagged with the number of the corresponding cluster.
I could then use that to generate masks to extract the information I need for each cluster from beta.nii.gz.
Is that correct?
3) The final information that I would need is the canonical hrf shape generated by FSFAST for a single event. I guess I could generate that by setting up a dummy analysis run with a single event of the desired duration and then look in the X variable in the resulting X.mat file?
Sorry for all the questions!
Joe
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Joseph Dien, Senior Research Scientist University of Maryland
E-mail: jdien07@mac.com Phone: 301-226-8848 Fax: 301-226-8811 http://joedien.com//