coordinates and volumelookup

Jan Hirschmann Jan.Hirschmann at MED.UNI-DUESSELDORF.DE
Fri Jun 4 15:21:29 CEST 2010

Dear all,


I am using the function ft_volumelookup with the AFNI atlas to find out
the areas belonging to certain MNI coordinates. Regarding this I have 3
little questions:


1)       If I create a grid from template brain T1 (spm2) and multiply
the .pos entries by 10 to convert to mm, as described in the example
matlab scripts on the fieldtrip homepage, the .pos entries are MNI
coordinates, right?


2)       When I use volumelookup to look up coordinates (I am giving a
mask as input which really has only 1 nonzero entry) I often get the
result: "no label found". Are there really that many places in the brain
which do not have a label in the atlas?


3)       When using the function I get the warning: "homogenous
transformation might be incorrect for AFNI file". Should I worry about
this? Labelling structures I recognize with the tool, e.g. thalamus,
works fine, so I guess labels and cords match.


Thanks for your help!



The aim of this list is to facilitate the discussion between users of the FieldTrip  toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis. See also and
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