[Marsbar-users] Very slow estimation
Status: Beta
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From: Jiansong Xu U. <jia...@ya...> - 2008-06-06 14:18:18
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Dear Friends: I'm trying calculate % signal changes of ROIS using Marsbar. It usually works very well. But, now the estimation is very slow and takes several hours for one ROI. It is much slower than the estimation of SPM2. SPM2 takes about 10 minutes to estimate for the whole brain analysis. Another issue is that for the same subject, marsbar perform estimation separately for each ROI. But, my previous experience is that Marsbar estimate once and than spit out % signal changes for different ROIs. Relative to my previous design, my current design use 6 motion parameters as covariates. I also used RobustWLS (http://www.bangor.ac.uk/~pss412/imaging/robustWLS.html) in my design to reduce the effects of motion. Marsbar print following message: Summarizing data with summary function: mean Re-estimating covariance Re-estimating whitening filter Initialising parameters Covariance estimate Model Temporal non-sphericity (over voxels) ...... ...... Any suggestions will be highly appreciated. Best -- Jiansong Xu, M.D., Ph.D. Associate Research Scientist Dept. of Psychiatry Yale Medical College 34 Park St., Room S-100 New Haven, CT 06519 |