Hi,
On 21 Feb 2008, at 15:08, Aziz Asghar wrote:
> Hi,
>
> I have performed a group analysis and can obtain a % BOLD value for a
> selected voxel of interest using Featquery. I have read the
> Featquery page
> and various emails on the FSL JISCmail but can not work out the
> answers to
> these two questions:
>
> 1) How would I go about obtaining the individual values that make up
> the
> mean % BOLD signal reported by Featquery? When I click on the
> “stats/pe1” I
> think I only obtain the pe values for each of the participants. In
> fact
> even if I click on “stats/varcope1” or “stats/tstats” or “stats/
> zstats” I
> still obtain the same values as for “stats/pe1” which I think are
> the pe
> values. Should this happen? I would have predicated that for example
> clicking on “stats/zstat1” I would obtain the z values for each of my
> participants.
I don't follow; exactly which results are the same, in the Featquery
table? The statistic values (e.g., 'mean') will be different for each
selected statistic image type. However, if you have only asked for a
single voxel to be interrograted (rather than a mask) then yes all the
statistic image types will find the same _location_ for the maximum,
as you are only looking at a single voxel.
> 2) With the “Convert PE/COPE values to %” option selected I get % BOLD
> values that look about right. How do I go about getting a % varcope
> associated with this % BOLD change? I can not work out how to
> convert the
> reported stats/varcope1 value to a % varcope1.
One easy way is to get the COPE values with and without the '%'
conversion, and then apply that factor to the square root of the
varcope.
We'll add the % conversion to be applied to the varcopes to the
Featquery TODO list.
Cheers, Steve.
>
>
>
> I am running FSL version 3.3. I am grateful for any advice.
>
> Best wishes,
> Aziz.
>
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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
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