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Dear Matthew: Ah a topic dear to me heart. We have taken the approach of stating the issue of Talairach space thusly: the images were normalized using the template image supplied with SPM-96 (99b). This template conforms to the space defined by the International Consortium for Brain Mapping project (ICBM) (NIH P-20 grant), and closely approximates the space described in the atlas of Talairach and Tournoux. The description, however, belies the difficulty in figuring out where one is in the atlas and in performing meta-analyses. Please note that the transform of Andreas' has an error in it which he corrected and wrote me later. The revised transform is: X' = 0.88 - 0.8 <---- here is the error Y' = 0.97Y - 3.32 Z' = 0.05Y + 0.88Z - 0.44 You may want to check your transform against it. I agree it would help if the SPM documentation was more precise about the issue of canonical Talairach space vs. all other spaces which approximate it. Best regards, Darren >Dear Fellow SPMers, > >One of our researchers here was recently asking how to determine estimated >Brodmann's areas using the coordinates from his SPM analysis. This >prompted me to look again at the thorny issue of the differences between >the MNI brains (which SPM96 and SPM99 use as templates) and the brain in >the Talairach atlas. These differences can mean that coordinates relative >to the MNI brain, such as those given by SPM, cannot be straighforwardly >related to the Talairach atlas; This is a topic which has been discussed >fairly fully last year on the list. > >I return to the topic for two reasons. Firstly, it seems to me that many >users of SPM appear to report that their data have been normalised to the >brain in the Talairach atlas. I wonder whether we the SPM users >could develop some way of pointing out to unwary readers that the coordinates >we report from SPM analyses on data normalised to the MNI brain may not be >directly comparable to the Talairach atlas. > >The second reason was that I have tried to come up with a very simple little >transform that does some kind of a job of transforming coordinates from >the MNI brain to those which match the Talairach atlas, and I would be >very grateful for any feedback or comments. I have tested the transform >against the only other one that I know of, kindly posted by Andreas >Meyer-Lindenberg last year, and believe that it does a better job of matching >the two brains. The new transform, and some description of the problem, >is available on a web page: > >http://www.mrc-cbu.cam.ac.uk/Imaging/mnispace.html > >Once again, I would be very grateful for any comments, > >Thanks a lot, > > >Matthew Darren R. Gitelman, M.D. ------------------------------------------------------------------------- Cognitive Neurology and Alzheimer's Disease Center E-mail: [log in to unmask] WWW: http://www.brain.nwu.edu Voice: (312) 908-9023 Fax: (312) 908-8789 Northwestern Univ., 320 E. Superior St., Searle 11-470, Chicago, IL 60611 -------------------------------------------------------------------------