[FieldTrip] ROI selection of beamformer grid points

[Marieke van de Nieuwenhuijzen]

Dear Fieldtrippers,

I am running my analyses on time courses reconstructed in source space. Basically, that means that my working dataset is a matrix of grid point x time. What I want to do now is do some analyses on a subset of that dataset, a bit analogous to selecting some sensors to restrict analyses to. Therefore, what I would ideally want to do, is select a subset of grid points corresponding to a specific location (for example only the occipital grid points, or only the grid points corresponding to a specific atlas label).

Does anyone have any suggestions about how I should go about selecting specific grid points? Is there perhaps some grid based atlas, or is it possible to select grid points based on their corresponding mni coordinates which you get after running ft_sourceinterpolate and ft_volumenormalise (in other words, is it possible to reverse ft_volumenormalise and ft_sourceinterpolate to map the mni coordinates to the grid points instead of the grid points to mni representation).

Any pointers would be much appreciated.

Best,
Marieke