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From: Marc S. <ms...@un...> - 2008-05-07 06:40:38
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hello We have collected some pilot fMR data (n=4) and are using GIFT to look for patterns of robust activation. We have extracted 20 components from the group data and have attempted to sort them using individualised (different) SPM.mat files for the n=4 subjects. However, we have a couple of questions for the more experienced GIFT users: 1) when we temporally sort the components using individual SPM.mat files we occasionally end up with odd correlation values ( > 1 or < -1, see attached). These values are derived from the text file that GIFT automatically generates while sorting components. What does it mean if an individual subject has a correlation of this magnitude with one of the group derived components? it is only meaningful to be looking at the overall group correlation value? 2) we are interested to know how the values for group correlations are calculated from the individual values, since the group correlations often vary significantly from the reported individual values? Is there a reference to help us with this issue. Thanks Marc - - - - - - - - - - - - - - - - - - - - - - - - Marc Seal ms...@un... Griffiths Research Fellow Melbourne Neuropsychiatry Centre The University of Melbourne c/o National Neuroscience Facility 161 Barry Street Carlton South 3053 AUSTRALIA ph: (+61 3) 8344 1861 fax: (+61 3) 9348 0469 www.psychiatry.unimelb.edu.au/mnc/ - - - - - - - - - - - - - - - - - - - - - - - - |