Positions to mri mapping

[Marie Smith]

Hi Robert,

I was hoping you could help with another question that I have related
to fieldtrip. I'm not sure if you recall the analysis that I have
discussed with you in the past so I will quickly summarize where I am
with it and then explain the problem.

I have performed an lcmv beamformer analysis to estimate the single
time course at a regular grid of points within the brain space. At
each point inside the space (from source.inside) i computed the
reverse correlation with the bubbles stimuli to establish the
information sensitivity of that point. I would now like to go from
these points in a regular array to a more interpretable brain space.
I have been trying to do this myself looking at your
sourceinterpolate and prepare_dipole_grid functions to establish what
the x, y and z co-ordinates correspond to in terms of the brain
orientations but I am getting lost in the functions.  Would you be
able to tell me? I am assuming z - is the vertical direction from
chin to scalp, but x and y?

The other solution that I thought off was to replace the energy
values coming out of sourceanalysis with a score for the correlation
of the classification image at that point with a given facial feature
(e.g. left eye). Could I then put that in source2full and
sourceinterpolate along with the mri to establish illustrate the
sensitivity to that feature overlayed on the mri?

Thanks for any advice / suggestions you may have,

Marie