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Hi, At the 3rd level, you should either use FLAME1 or FLAME1+2. Note that the FLAME options are not 'more stringent' than OLS, they are more accurate. (Both the FLAME and ME OLS options are the same basic model, i.e. mixed-effects.) Cheers. On 26 Oct 2007, at 14:57, rajani sebastian wrote: > Hi all > > I have a question regarding higher level analysis using FSL. My > fmri experiment is a blocked design and consists of two sessions > (approximately 6 > minutes each session). I collected data from 10 subjects. I used > first level analysis for analyzing each sessions data. Then, i > used higher level analysis for combining the two sessions for each > subject using FIXED effects, cluster thresholding p< 0.05. > Finally, i plan to combine all the subjects together. The question > i have is regarding the stats section in higher level analysis. > Should i used simple OLS or FLAME 1+2? I read in the FSL manual > that simple OLS is the least accurate of all the ME options. So do > i use FLAME 1+2 as this is a suggested option if the number of > subjects is less. What i am concerned about is whether i would find > any activation since this procedure is very stringent. Also, what > thresholding level should i use, cluster or uncorrected or voxel > based ? > > Thanks > Rajani ------------------------------------------------------------------------ --- Stephen M. Smith, Professor of Biomedical Engineering Associate Director, Oxford University FMRIB Centre FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK +44 (0) 1865 222726 (fax 222717) [log in to unmask] http://www.fmrib.ox.ac.uk/~steve ------------------------------------------------------------------------ ---