Hi Stefan,
For help with power analyses in fMRI, you can take a look at http://fmripower.org/
.
For drawing ROIs, you can use MRIcron and/or FSLview. There are also
several atlases within FSL (viewable with FSLview) that might be
helpful. Pickatlas (from Wake Forest University) is another tool you
can use for creating ROIs.
Cheers,
David
On Oct 26, 2009, at 8:12 AM, Stefan du Plessis wrote:
> Hello
>
> I have only recently started working on FSL and have a basic
> question on the
> statistics. I am only at the beginning of my research venture and
> have yet
> to master the stats involved. For the time being I need to work out
> a power
> of analysis for my groups for my research proposal.
>
> Is there a way I can use the software to compute a sample size
> needed/ power
> of analysis of my planned groups for a fMRI study? I have used FLAME
> but I
> am not sure what stats will be of relevance for a power of analysis
> for my
> initial proposal.
>
> What do people generally do?
>
> Do they use the amount of voxels that activated in a region of
> interest
> above the Z threshold?
>
> What tools can I use to define a region of interest? I am using a
> Stroop
> task and would like to use anatomically pre-defined regions of
> interest
> (Anterior Cingulate etc etc.) first. Thereafter I would like to
> experiment
> by subtracting the Color Naming and Word naming of one sample from the
> Interference task from an independent group and use this as a region
> of
> interest.
>
> Would it work say to count the number of voxels in an anatomical
> area then
> compare it to the number of voxels that activated above my threshold
> in a
> post FLAME analysis? Is there an easy way in FSL?
>
> I have yet to attend the FSL workshop as you can undoubtedly see and
> I am
> trying to self train in the mean while. I have run a mean analysis
> as well
> as a T-test successfully, but I am still a bit unclear on these
> rather vital
> points!
>
> Thank you very much!
>
> Stefan du Plesis
> CUBIC, Cape Town, South Africa
--
David V. Smith
Graduate Student, Huettel Lab
Department of Psychology and Neuroscience
Duke University
http://www.mind.duke.edu/huettellab/
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