I saw a talk at a neuroscience informatics conference here at
NIH a couple of years ago that stated strongly that functional
activation didn't seem to follow the gyral architecture (well-known)
nor the cytoarchitecture/Brodmann's very well at all. The talk showed
that activation from subject to subject can be predicted very well only
by mapping gene expression in the neurons. I believe some of this was
PET, and some of it was posthumous dissection (especially the detailed
comparison with Brodmann's cytoarchitectural areas).
I think the speaker was from UCLA, anybody familiar with this work?
rich
Russ Poldrack wrote:
> Eli - this is a FAQ and I feel like a broken record, but here goes:
>
> The idea of an automated one-to-one mapping between stereotactic
> locations and anatomical structures is highly problematic. The fact
> that the Talairach atlas (and sites like the Talairach Daemon) support
> this function does not make it any less problematic. There are a
> couple of problems. One is that volumetric spatial normalization does
> not absolutely align structural features; that is, if you normalize
> all of your subjects to a common space, and then classify which
> particular brain bits fall at a particular location for each subject,
> you will see that there is not perfect alignment across subjects.
> Various people (e.g., the MNI group) have produced probabilistic
> atlases showing this, and some of this information is available
> through the Talairach Daemon. Thus, the best you can do is say that
> you are in a particular structure with some probability.
>
> Second, there is the issue of structure-function association. Work by
> Amunts and a number of others has shown that cytoarchitecture (e.g.,
> Brodmann's areas) does not follow gyral anatomy. This is particularly
> the case in places like prefrontal cortex (e.g., see Amunts' work on
> area 44/45). Thus, you can't simply go from a stereotactic location
> to a Brodmann's area.
>
> Third, the Talairach atlas presents what are essentially guesstimates
> about where particular Brodmann's areas fall - they are not based on
> direct histology of the Talairach brain. Going from Talairach
> coordinates to Brodmann's areas by means of the Talairach atlas is
> thus highly suspect.
>
> I will not pretend to have the right answer to this question, but the
> approach that I try to instill into my students is to actually
> understand the anatomy where they are seeing activation, looking both
> at group maps and individuals. This is best done by working with a
> high-quality anatomical atlas; we like the Duvernoy atlas. In the end
> the goal should be to have a good enough 3-D mental model of brain
> anatomy that you can do this without the atlas, but that takes a long
> time indeed.
>
> If you feel really strongly about localizing to Brodmann's areas, then
> one approach is to use the probabilistic maps created by the Julich
> group (http://www.fz-juelich.de/ime/ProbabilityMaps_eng.html). With
> these maps, you can provide a probability that your activation is in
> any of the particular areas for which there are maps. Unfortunately
> these are only available for a limited number of areas.
>
> I recommend that you read Matthew Brett's paper on localization in
> functional imaging, which discusses these and other issues quite nicely.
>
> cheers,
> russ
>
>
>
> On Mar 4, 2005, at 11:55 AM, Eli Packer wrote:
>
>> Hi,
>> I need a way to translate voxel coordinates to their corresponding
>> regions. This is the task of Talairach. I saw that there are applets
>> that can be downloded but it will not help me since I want to use
>> this database in my own code. I also do not want to be involved in
>> converting SPM code or such. Just a simple database with pairs of
>> coordinate and regions is enough. Any ideas how to obtain it?
>>
>> Thanks a lot,
>> Eli Packer
>>
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> ---
> Russell A. Poldrack, Ph.D.
> Assistant Professor of Psychology, UCLA
> Franz Hall, Box 951563
> Los Angeles, CA 90095-1563
> email: [log in to unmask]
> phone: 310.794.1224
> fax: 310.206.5895
> web: http://www.poldracklab.org
> /
--
rich hammett SSCC/DIRP/NIMH
National Institutes of Health
Building 10, Room 1D80
10 Center Drive, MSC1148
Bethesda, MD 20892-1148
ph 301-402-8416 fax 301-402-1370
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