[caret-users] Mapping BrainVoyager statistical volumes to PALS atlas

[Donna Dierker]

Hi Manny,

I have no Brainvoyager experience, but I map NIfTI to PALS often.  Which 
version of Caret are you running?  John Harwell fixed some NIfTI issues 
a while back, but I don't recall exactly when.  If you are using the 
most recent version (Version 5.61 - 12 November 2008), then those 
changes should be incorporated already. 

The volume issue must be resolved before the next issue can be 
pinpointed:  Why isn't the AFNI surface a good proxy for Brainvoyager, 
since both packages use the Talairach & Tournoux 1988 (T&T88) recipe for 
spatial normalization?  Or at least they used to; I'm guessing most AFNI 
users now use @auto_tlrc to spatially normalize their subjects.  While 
it still uses the T&88 bounding box / scale, it uses an affine transform 
to get there, rather than the piecewise linear process defined in 
T&T88.  I do not know whether Brainvoyager now offers an affine option; 
however, the PALS AFNI surfaces were normalized using the old, manual 
method, because the affine option did not exist when these surfaces were 
created.

If it is really true that the PALS AFNI surfaces are poor proxies for 
Brainvoyager, then we will need to consider developing Brainvoyager 
surfaces.  But I would like to see some evidence before adding that task 
to our queue.

Donna

On 11/30/2008 07:55 PM, Manny Vindiola wrote:
> Hi Caret users,
>
> I was wondering if anyone has had any success mapping a brainvoyager
> VMP (statistical volume) converted to nifti format to the PALS
> surface? There are two problems I have run into, the first is the
> volume does not correctly align with the anatomical and secondly the
> dimensions of a VMP and the  AFNI tlrc volumes differ. The method of
> creating a talairached statistical volume is the same procedure used
> by afni. Can anyone offer any guidance or help?
>
> thanks,
> Manny
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