[FieldTrip] In the forward problem, how are the points for the grid.inside and grid.outside defined?

["Jörn M. Horschig"]

Hi Ana,

inside and outside just describe whether the grid point is inside or 
outside the brain. You can plot this to see for yourself:
% plot only what is inside the brain
figure;
ft_plot_vol(vol, 'edgecolor', 'none'); alpha 0.4;
ft_plot_mesh(grid.pos(grid.inside,:));

% plot the whole grid
figure;
ft_plot_vol(vol, 'edgecolor', 'none'); alpha 0.4;
ft_plot_mesh(grid.pos(:,:));

FieldTrip will use that information automatically to only use grid 
points inside the brain, so yes, you can use the whole grid to compute 
the leadfield matrix. If you do not want that, you can modify 
grid.inside and grid.outside yourself.

Have fun fieldtrippin' :)
Jörn

On 6/28/2013 9:31 AM, Ana Sofía Hincapié Casas wrote:
> Hi,
>
> I´am new in FieldTrip and I would like to what are the grid.inside and 
> grid.outside points and if I could used the whole grid to calculate 
> the leadfields.
>
> Thanks in advance for the help you could bring me.
>
> Regards,
>
> -- 
> Ana Hincapié
>
>
> _______________________________________________
> fieldtrip mailing list
> fieldtrip at donders.ru.nl
> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip


-- 
Jörn M. Horschig
PhD Student
Donders Institute for Brain, Cognition and Behaviour
Centre for Cognitive Neuroimaging
Radboud University Nijmegen
Neuronal Oscillations Group
FieldTrip Development Team

P.O. Box 9101
NL-6500 HB Nijmegen
The Netherlands

Contact:
E-Mail: jm.horschig at donders.ru.nl
Tel:    +31-(0)24-36-68493
Web: http://www.ru.nl/donders

Visiting address:
Trigon, room 2.30
Kapittelweg 29
NL-6525 EN Nijmegen
The Netherlands

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