You might also take a look at:
Stevens M, Calhoun VD, Kiehl KA. (2005): Hemispheric Differences in
Hemodynamics Elicited by Auditory Oddball Stimuli. NeuroImage 26(3):782-792.
We have some (non gui) scripts to implement this if you are interested.
Regards,
VDC
> -----Original Message-----
> From: SPM (Statistical Parametric Mapping)
> [mailto:[log in to unmask]] On Behalf Of Marko Wilke
> Sent: Monday, July 09, 2007 1:25 AM
> To: [log in to unmask]
> Subject: Re: [SPM] Creating lateralisation indices
>
> Dear Pieter,
> dear Mahinda,
>
> just to add my belated 2 cents on this: as (almost) always, there are
> many roads that lead to Rome. The elegant script Pieter posted will
> yield lateralization curves which I also prefer as they will
> give a much
> better idea of how the data behaves over a range of
> thresholds, instead
> of only looking at a snapshot derived from "significant"
> voxels, however
> defined.
>
> May I add that, for comparison purposes, it may still be nice
> to have a
> single value that allows comparing LIs between subjects,
> which ideally
> will be based on such curves. By now, you will not be
> suprised anymore
> to hear that such an approach is indeed available within my
> LI toolbox
> which I am happy to send to anyone interested enough to send me an
> e-mail :) I know, I should have a website, I am working on that...
>
> Best,
> Marko
>
> Pieter Vandemaele schrieb:
> > Dear Mahinda,
> >
> > I have written a script to calculate lateralization indeces
> > (attachment). It's a pre-beta version, it would be nice if
> someone else
> > would like to test it.
> > If someone has comments, feel free to contact me. However,
> changes may
> > take some time due to holidays and higher priority tasks.
> > Regards
> >
> > Pieter
> >
> > Mahinda Yogarajah schreef:
> >> Dear List Users,
> >> I am trying to create a lateralisation index for fMRI
> activation in
> >> verbal
> >> fluency tasks in individual subjects. I am using the VOI
> button to
> >> create a
> >> sphere of 5mm radius around a peak activation. I am then
> using a script
> >> that I have found posted on this list to calculate all the
> beta values
> >> for
> >> the voxels from which I am calculating a mean. My
> questions are as
> >> follows:
> >>
> >> 1) Using the voi button I get no option to 'adjust data' -
> by default it
> >> does not adjust - is there a reason I cannot choose the
> adjust option and
> >> perhaps more importantly what does this adjust for exactly ?
> >>
> >> 2) Using the VOI button I note that it only picks up
> voxels that are
> >> significant at whatever threshold I am using - is this a
> problem in
> >> view of
> >> the fact that when I mirror ny VOI to the other side
> (which shows less
> >> activation in the language task), it will contain far
> fewer voxels in
> >> a VOI
> >> of the same size. Is there a way around this ?
> >>
> >> Thank you.
> >>
> >> Mahinda
> >>
> >
>
> --
> =====================================================================
> Marko Wilke (Dr.med./M.D.)
> [log in to unmask]
>
> Universitäts-Kinderklinik University Children's Hospital
> Abt. III (Neuropädiatrie) Dept. III (Pediatric neurology)
> Hoppe-Seyler-Str. 1, D - 72076 Tübingen
> Tel.: (+49) 07071 29-83416 Fax: (+49) 07071 29-5473
> =====================================================================
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