Question about the coordinates system

Hi,

Thank you for your work, this package is very useful!

I had a question about the coordinates system:

- Does the x=0 correspond to the bregma?
- I noticed that y=0 and z=0 seem to be outside of the nervous system. Do they correspond to something?

I didn't manage to find this information on the Allen Institute website.

Thanks,
Aurélien W.