Dear Tom and others, I have PET-data of 9 subjects (one scan per subject) and want to correlate these Scans with a behavioral measure within the framework of snpm. Since the function snpm_MSC.m (Multi-subject simple correlation) did not work, I tried the same thing for single subjects (the function snpm_SSC.m). There I entered "9" as size of exchangability block (option either 3 or 9). Now I am wondering if this is the right snpm-function (or at least a correct work-around) for analyzing the PET data, since the function I used is not meant to be used for multi-subject designs. Thanks a lot, Thilo -- Thilo Kellermann RWTH Aachen Pauwelstr. 30 52074 Aachen Tel.: +49 (0)241 / 8089977 E-Mail: [log in to unmask]