[Mne_analysis] vertex coordinates

[dgw]

I would recommend another technique for a couple of reasons:

1. The numbering system only has a rough correspondence for many 
vertices and can be wildly off for others. (which makes that more difficult)

2. actually calculating a fit that makes sense is extremely difficult 
and is exactly what FreeSurfer is designed to do, which is what the 
purpose of the morphing options in mne are designed to take advantage of.

So experimenters can morph to an individual (either from your experiment 
or fsaverage, or an average from your experiment). Then extract the data 
from similar labels in the annotations.


If those don't fit your needs and the experimenter truly wants the 
contralateral non-functionally defined region (this is very specific to 
the region and reasons that the experimenter is interested in it), then 
look into the xhemi work (Doug Greve is the major developer of it) found 
here:
http://surfer.nmr.mgh.harvard.edu/fswiki/Xhemi

This page has a link to the paper which should be read.

Note, that there is a separate fsaverage_sym which is different from 
fsaverage (this may mean it is not safe to assume the numbering is 
symmetrical, though this would be a question for the freesurfer list). I 
think if you want true symmetry between the surfaces this is the 
technique to apply. Think carefully though before going down this road: 
real brains are not symmetrical, so in many cases it will not make sense 
to head down that road.

hth
d



On 1/7/16 7:21 PM, Rezvan Farahi wrote:
> Yes, absolutely not for single subjects; there the numbering is in the
> original space and not in the downsampled space and not equal number of
> vertices for the two hemispheres.
> For the stc files defined in the downsampled space there seems to be a
> rough correspondence.
> Is there a way I can accurately find the mirror vertices?
>
> Thanks,
> Rezvan
>
>
> On Fri, Jan 8, 2016 at 12:15 AM, dgw <dgwakeman at gmail.com
> <mailto:dgwakeman at gmail.com>> wrote:
>
>     It is important to note: while this may be true for fsaverage (I haven't
>     done a check of this) it is definitely NOT true for any individual
>     participant's brain.
>
>     hth
>     d
>
>     On 1/7/16 7:12 PM, Rezvan Farahi wrote:
>     > Sorry, my bad, sorted. the location for 0 does pair with 10242, 1 with
>     > 10243 and so on... thought had checked this before.
>     >
>     > On Thu, Jan 7, 2016 at 11:48 PM, Rezvan Farahi <rezvan.farahi at gmail.com <mailto:rezvan.farahi at gmail.com>
>     > <mailto:rezvan.farahi at gmail.com <mailto:rezvan.farahi at gmail.com>>> wrote:
>     >
>     >     Hi all,
>     >     I was wondering, for source estimates in the fsaverage space, is
>     >     there a quick way of determining the mirror vertices bilaterally?
>     >     (e.g.vertex 0 is in the left hemisphere, what's the opposite in the
>     >     right?)
>     >     Sorry if it's explained somewhere in the tutorials, hadn't come across.
>     >
>     >     Many thanks,
>     >     Rezvan
>     >
>     >
>     >
>     >
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