# MEG-MRI coregistration

**URL:** <https://mne.discourse.group/t/meg-mri-coregistration/1040>\
**Category:** Mailing List Archive (read-only)\
**Tags:** list-archive\
**Created:** [July 8, 2016, 2:52pm UTC](https://mne.discourse.group/t/meg-mri-coregistration/1040 "2016-07-08T14:52:30Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/mne/original/1X/85cc6bd2b69cb698a166dc6d880fb550510d0144.jpeg) [@system](https://mne.discourse.group/u/system)\
**Post date:** [July 8, 2016, 2:52pm UTC](https://mne.discourse.group/t/meg-mri-coregistration/1040/1 "2016-07-08T14:52:30Z")

</div>

Dear list,

I'm using the MNE Coregistration GUI tool to obtain the transformation  
matrix.

I'm not able to figure out what co-ordinate system the scalp (shown in GUI)  
is in and which MRI volume it is directly related to - /mri/T1.mgz or  
/mri/orig/001.mgz ?

Thanks,

---

<div class="post-metadata">

**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/mne/original/1X/85cc6bd2b69cb698a166dc6d880fb550510d0144.jpeg) [@system](https://mne.discourse.group/u/system)\
**Post date:** [July 10, 2016, 11:44am UTC](https://mne.discourse.group/t/meg-mri-coregistration/1040/2 "2016-07-10T11:44:43Z")

</div>

hi Kousik,

> I'm using the MNE Coregistration GUI tool to obtain the transformation  
> matrix.
> 
> I'm not able to figure out what co-ordinate system the scalp (shown in GUI)

I suppose it's in Freesurfer surface RAS.

> is in and which MRI volume it is directly related to - /mri/T1.mgz or  
> /mri/orig/001.mgz ?

it should be using T1.mgz

HTH  
Alex