sulci projection

cedric clouchoux · Post by **cedric clouchoux** » Mon Dec 13, 2004 5:17 pm

Hi there
i need to project sulci, and i'm looking at the Arnaud stuff in brainvisa. I just have questions about .gyr and .trl files. I played with these files several times, but i don't think i really know what they are.
I have a hierarchy with a set of selected sulci. Can i obtain these files (.gyr & translation file) from it?
I think the .gyr file is here to specify which sulci must be projected, but i don't really understand the translation one. Can i use an existing one (i.e. "/shared-main/nomenclature/translation/gyri.trl"? Or have i to rebuild a new one (which seems to be quite long and tough)?
thanks a lot
ced

cachia · Post by **cachia** » Mon Dec 13, 2004 7:03 pm

Hi Cedric,

These two files are used to select the sulci that have to be projected :

- the .gyr file define sulci to be projected (for instance S.C. and S.F.sup.). Initially, this file was developed for the parcellation in gyrus and so require some information related to the gyrus : each line contain the name of a gyrus (delimited by / and / ) and the set of sulci that define this gyrus (deilimited by / and / ). For instance if you want to project the sulci S1, S2, S3, you just have to fill the .gyr with the line :
/ gyrus1 / S1 S2 S3 /

The information relative to the gyrus name (here gyrus1) does not have any utility in this context...

(Be carefull : do not forget the space around the / )

- the .trl file provide a translation (if necessary) between the sulcus name present in the sulcu s graph and your own sulcus name (ie the sulcus you have put in the .gyr file). For instance, if for you the central sulcus (S.C.) correspond to the merge of the several sub-pieces (used by system for the automatic labellisation) S.C.sup. , S.C.inf. , S.C.sup.r.GPoC., S.C.sup.r.GPeC. , S.C.inf.r.GPoC. and S.C.inf.r.GPeC. you have to fill the .trl file with the following lines :

%S.C.
%S.C.sup. S.C.
%S.C.inf. S.C.
%S.C.sup.r.GPoC. S.C.
%S.C.sup.r.GPeC. S.C.
%S.C.inf.r.GPoC. S.C.
%S.C.inf.r.GPeC. S.C.

As you can see, the S.C. sulcus does not have a translation wich means that its label won't change.

You can of course use the .trl file provided with the pack but make be sure that the translation actully correspond to what you want...

I'm sorry if it is a little complex, but there is not any standard for the sulcus (nor gyrus) nomenclature...

Arnaud

cedric clouchoux · Post by **cedric clouchoux** » Tue Dec 14, 2004 11:31 am

thanks a lot

- the .trl file provide a translation (if necessary) between the sulcus name present in the sulcu s graph and your own sulcus name

If i think sulcus names are ok, do i need to specify a .trl file? Or do i have to have a file with no translation (i.e. just the original sulcus names without any translation)?
ced

cachia · Post by **cachia** » Tue Dec 14, 2004 6:17 pm

Even if the sulcus name are ok for you, you have to provide a .trl file (ie, as you say, just with the original sulcus names without any translation).

Arnaud