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
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Stephen M. Smith, Professor of Biomedical Engineering
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FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
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