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Thanks, Torben. I appreciate the input. Exactly what I needed to know. Warm regards, Jeff _____ From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]] On Behalf Of Torben Ellegaard Lund Sent: Monday, September 24, 2007 10:42 AM To: [log in to unmask] Subject: Re: [SPM] Smoothing for native space data & ROIs ? Hi Jeff If you plan to use subject specific ROI's in native space I would suggest to not smooth at all. This would give you less partial volume effect, and you are already obtaining the SNR gain by averaging within your ROI. If you are using standard space ROI's you should smooth in order to compensate for imperfect spatial normalisation e.g. 8mm or even more. Best Torben Torben Ellegaard Lund Assistant Professor, PhD The Danish National Research Foundation's Center for Functionally Integrative Neuroscience (CFIN) Aarhus University Aarhus University Hospital Building 30 Noerrebrogade 8000 Aarhus C Denmark Phone: +4589494380 Fax: +4589494400 http://www.cfin.au.dk [log in to unmask] On 24/09/2007, at 16.10, Jeff Browndyke, Ph.D. wrote: Are there any guidelines or suggestions on how much (or little) smoothing should be performed if one is interested in analyzing data in native space? We're planning on capturing native ROI-bounded BOLD activity, but I'm not certain if smoothing should be applied prior to deriving the individual, fixed effect results. We're likely to try Marsbar, as well as just collecting summary ROI activation/voxel ratios. Thanks for any tips or pointers. Regards to all, Jeff ------------------------------------------ Jeff Browndyke, Ph.D. Assistant Professor - Dept. of Psychiatry Duke University Medical Center [log in to unmask] ------------------------------------------ __________ NOD32 2546 (20070924) Information __________ This message was checked by NOD32 antivirus system. http://www.eset.com