XJVIEWER MNI vs Talairach

[lion gao]

Dear Xjviewer,

 

As I can see in the FAQ, the volume table xjview gives is MNI coordinate, and anatomical label is from  AAL. While I do see that many time when I click on a point, it gives BA areas as well, e.g. by (-20, 0 62), Xjview will tell me it's BA6 /Frontal_Sup_L (aal). Then I find in Talairach that this ponit  (-20, 0 62) belongs to BA6, but the anatomical name is Middle Frontal_left.

 

My question is that whether BA areas are all from Talairach but not aal, right? Should I transfer MNI to Talairach when I check  (-20, 0 62) in  Talairach? or there is no need to do that, and let it be ?

 

I not sure whether this is a XJview problem or a general problem in SPM. Anyhow, thanks very much for any suggestion!

Best Wishes,

Gao

[Xu Cui]

All coordinates in xjview is in MNI space. If the talairach database you use requires a coordinate in talairach space, then yes, you need to convert MNI to TAL first.

The coordinate to anatomy mapping database used in xjview is from WFU_PickAtlas

Xu

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Xu Cui
Department of Psychiatry and Behavioral Sciences
Stanford University
Blog: http://www.alivelearn.net
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[lion gao]

Thanks for the answer!

 Just a bit curious for a further question.

The Brodmann Area can only come from Talairach but not MNI space, right?

So will  XJVIEW convert the MNI coordinate (-20, 0 ,62),   to TAL ones ( ?, ? ,?),   before it showing e.g., "BA 6",  or it is directly from MNI and omit the tiny difference ?

 

2009/11/23 Xu Cui <cuixi...@gmail.com>

[Xu Cui]

WFU_PickAtlas has already done the MNI <-> TAL conversions. xjView uses the wfu-pickatlas database without further conversion.

> The Brodmann Area can only come from Talairach but not MNI space, right?

The BA area was label in TAL first and then (I think) somebody converted them in MNI space. A brief history: In 1909 Korbinian Brodmann published the Brodmann map;in 1988 Talaiirach and Tournoux published their Talairach atlas. The Brodmann areas labeled in Talairach atlas was by visual estimation and thus was an approximation. SPM99 and later uses ICBM152 template (MNI space).

I find this link is very useful: http://imaging.mrc-cbu.cam.ac.uk/imaging/MniTalairach

When reporting an anatomical label of an activation region, I think it's probably a good idea to get a statistics of "how many voxels in this cluster are in xyz region", then pick up a meaningful label the community accepts -- instead of relying on the label of a single voxel (albeit peak voxel).

Best,
Xu

[lion gao]

---> WFU_PickAtlas has already done the MNI <-> TAL conversions. xjView uses the wfu-pickatlas database without further conversion.

 

So it means that the xjview actually gives TAL coordinates rather than MNI ones ?!--I do notice the difference between XJVeiw and standard SPM output!

I think the AAL( the toolbox for SPM2 and SPM5) does a similar work, it transfer the coordinates before label the anatomical position, and I also find the slight difference between comparing the coordinates.

 

BTW, thanks for the links. It says there is no absolute anaswer to clear cut the difference of MNI and TAL. Indeed, most of time, to directly look at the site position seems to make sense, given the difference among individuals.

 

Best Wishes,

Gao

 

 

2009/11/23 Xu Cui <cuixi...@gmail.com>

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[Xu Cui]

xjview gives out MNI, as SPM does.

xjview should output *exactly identical* results with SPM. Please let us know when you find any difference.

Xu

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