Hi Russ & Trevor,
Simon Eickhoff has developed a toolbox for SPM that allows to directly
integrate functional maps and the probabilistic cytoarchitectonic atlases
from the Zilles lab. It can be downloaded from:
http://www.fz-juelich.de/ime/spm_anatomy_toolbox
The paper describing the concept and methodology of his toolbox is in press
at NeuroImage, you can get it from the "Articles in Press" section of
NeuroImage @ ScienceDirect:
http://www.sciencedirect.com/science?_ob=JournalURL&_cdi=6968&_auth=y&_acct=C000010182&_version=1&_urlVersion=0&_userid=125795&md5=511ffd4454abf6d5c6bcac485183353c
Cheers,
Klaas
At 16:54 07/03/2005, you wrote:
>Trevor - there is certainly evidence that cytoarchitectural areas differ
>both in their location and extent across subjects, suggesting that there
>will not be any one-one mapping of location and structure between subjects
>(e.g., Amunts et al. for Broca's area, Rajkowska & Goldman-Rakic for
>dorsolateral prefrontal cortex). You are correct that this creates
>difficulty in interpreting voxel-based analyses. The field generally
>glosses over this by smoothing the data to an extent sufficient to
>overcome this variability.
>
>cheers
>russ
>
>
>On Mar 7, 2005, at 3:14 AM, Smart, Trevor wrote:
>
>>I am relatively new to fMRI and the mailing list and my question may be
>>rather naive. I was hoping to do the same as Eli - map the coordinates of
>>the standard fMRI space (eg Telairach) to regions of the structural brain
>>atlas. If I understand your point, functional maps do not map directly to
>>structural maps as everyone is different. Instead a probabilistic approach
>>can be used. However, how does this relate to differences between
>>individuals in their functional maps. If there was no difference, then
>>couldn't an atlas be redefined functionally? If this still remains a
>>probabilistic map because of inter-subject variability then isn't this a
>>problem for the smallest region we can identify - a voxel. If this is the
>>case, does this create issues in interpreting voxel by voxel analyses? This
>>seems quite fundamental, but probably just reflects my lack of experience in
>>the field.
>>
>>Trevor
>>
>>-----Original Message-----
>>From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]]On
>>Behalf Of Russ Poldrack
>>Sent: 04 March 2005 20:58
>>To: [log in to unmask]
>>Subject: Re: [SPM] Talairach database
>>
>>
>>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
>>>
>>>__________________________________________________
>>>Do You Yahoo!?
>>>Tired of spam? Yahoo! Mail has the best spam protection around
>>>http://mail.yahoo.com
>>---
>>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/
>>
>>
>>
>---
>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/
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