Hi - yes, at the moment these % changes don't make sense at higher level,
as the "baseline level" used to convert PE or COPE into a % doesn't mean
anything useful in the 2nd-level input data (which is COPEs from first
level, not image data). Therefore you would need to convert the non-% data
yourself by going back to the first-level baseline levels. Sorry!
Cheers.
On Wed, 17 Nov 2004, Jane Aspell wrote:
> Hi all
>
> I'm trying to get % change values out of Featquery and am having some
> trouble - the output gives me mean values of 2000-4000! I'm running
> Featquery on the results of a higher level analysis - a fixed effects
> analysis which combined 5 sessions for a single subject - so am selecting
> something.gfeat/copeX.feat directories.
> It was suggested to me that my mask (a retinotopic map) could be including
> voxels outside of the brain and this could be causing the huge values, but
> when i tried eroding the mask it made almost no difference.
> When i run Featquery on the first level directories from single sessions I
> get mean values around 0.2, which seems reasonable.
> any idea what the problem is? my experiment was a simple block design.
>
> many thanks,
>
> Jane Aspell
>
Stephen M. Smith DPhil
Associate Director, FMRIB and Analysis Research Coordinator
Oxford University Centre for Functional MRI of the Brain
John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve
|