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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
> =====================================================================