[FieldTrip] Query about source/gridpoint size after ft_prepare_sourcemodel

Eelke Spaak e.spaak at donders.ru.nl
Tue Jul 24 09:16:06 CEST 2018

Hi Ravi,

Beamforming will estimate source activity at *point* sources; in other
words, the grid points have no spatial extent (i.e., they are

> If so, is the only way to extract 'larger' sources to fit a
> whole-brain grid (e.g. using the 4mm-spaced source template provided by FT),
> identify gridpoints after ft_sourceanalysis that fall within a specified
> Euclidean distance (e.g. 5mm) of the functional atlas MNI coordinates, and
> then e.g. average over all those gridpoints?

Yes, that is definitely a valid approach. You will probably not need
to use such a finely spaced grid if you end up averaging over grid
points anyway. Typically, the spatial filters for neighbouring grid
points will be highly correlated.


> Thanks in advance!
> Ravi
> --
> Ravi Mill, PhD
> Post-doctoral researcher
> Center for Molecular and Behavioral Neuroscience (CMBN)
> Rutgers University
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> https://doi.org/10.1371/journal.pcbi.1002202

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