Dear Alexander:

In your opinion, how does LPBA40 (http://www.loni.ucla.edu/~shattuck/resources/lpba40/) compare with the n30r83? LPBA40 only has 56 structures, but it was constructed from 10 more subjects. It seems both n30r83 and LPBA40 have maximum probability maps. 

I do not want to get into the details of comparing those two templates. As a user, I just want to choose one template to mask regions in my fMRI data. Any suggestions?

Best,

Carlton

On Sat, Feb 5, 2011 at 2:56 PM, Alexander Hammers <[log in to unmask]> wrote:

Dear Steffie,

Brodmann areas are histological entities; you can therefore only really get to them via histology. There is a long-term initiative under way in Jülich, Germany to provide such maps via histological workup of ten brains and spatial transfer to MNI space - see http://www.fz-juelich.de/inm/inm-1/index.php?index=396 and papers by Zilles K, Amunts K, Eickhoff E et al.

They are great but don't exist for all areas.

The next best thing is to define your regions based on multiple brains. The good news is that for major sulci, there is, on average, actually a reasonable correspondence between histology and macroscopic landmarks (which you can see on MRI), see e.g. Figure 6 in Hammers A et al. Hum Brain Mapp 2007.

One such atlas is our maximum probability map in MNI space (Hammers A, Allom R et al. Hum Brain Mapp 2003; since then expanded to include 83 regions and now based on 30 brains (n30r83; see Gousias IS et al. Neuroimage 2008 for the additional region definitions)), which you can get by agreeing to a one-page free academic licence (attached).

There are many more atlases based on _single_ brains, including AAL (Tzourio-Mazoyer et al. 2002); our earlier segmentation of the same brain (Hammers et al. 2002); and digitalized versions based on the single Talairach hemisphere (minus cerebellum) (e.g. WFU Pickatlas). However, single brain / hemisphere atlases are by definition not representative and are therefore not likely to well represent your subject under study. This can be, and has been, quantified for AAL and PickAtlas versus the maximum probability map (Rodionov R et al.Magn Reson Imaging 2009).

The most exhaustive quantification of the errors involved in single subject atlasing is in Heckemann RA et al. Neuroimage 2006. In terms of spatial overlap, for single atlases, you loose five Dice index points compared to the maxprobmap. You'd need to train a student for several months to improve that much, and by using a maximum probabilty map you get the same improvement for free :-).

Obviously there are other more involved and more accurate forms of atlasing (see e.g. Heckemann RA et al. Neuroimage 2010 for one example and a review), but for working in MNI space with low-res techniques (fMRI, PET, SPECT, MEG, etc.) I think maxprobmaps are an excellent compromise.

Hope this helps,

ATB, A

PS: If you want the n30r83 maxprobmap, just email me off-list if the licence is acceptable to you (it essentially asks to cite our work and not use it commercially).

On 4 Feb 2011, at 19:38, Michael T Rubens wrote:

WFU pickatlas

http://fmri.wfubmc.edu/software/PickAtlas

cheers,

Michael

On Fri, Feb 4, 2011 at 10:30 AM, Steffie Tomson <[log in to unmask]> wrote:

Hi Everyone –

 

I’d like to pull BOLD data from a set of anatomical regions.  For example, I’d like to look at traces in the anterior cingulate or the left ITG.  Does anyone know how to find a database of MNI-normalized anatomical regions like this?  Ideally, somewhere to download individual masks for anatomical regions, or even Brodmann’s areas?

 

Thanks so much,

Steffie

 

-- 
Research Associate
Gazzaley Lab
Department of Neurology
University of California, San Francisco