[FieldTrip] Assistance Request for Displaying Values of Electrodes Outside Brain Contour with ft_topoplotER function

[二姬]

Dear FieldTrip Community,

I am Chengyuan Wu from Ningbo Kangning Hospital, reaching out for guidance
on an issue I've encountered while working with EEG topographical mapping
with ft_topoplotER function, specifically using the EGI 129 electrode
system.

My current challenge is with electrodes positioned outside the brain
contour on the topoplot. While the electrode positions relative to the
brain are correct, those located outside the brain contour do not display
their corresponding values, appearing as blank areas on the map.

To provide some context, here is a segment of my code:

cfg = [];
cfg.layout =
'F:\eeg_ningbo\fieldtrip-20211209\template\electrode\AdultAverageNet128_v1.sfp';

[layout, ~] = ft_prepare_layout(cfg);
% Scaling layout to avoid electrodes clustering in the center of the brain
layout.pos(:,1) = layout.pos(:,1) * 1.7;
layout.pos(:,2) = layout.pos(:,2) * 1.7;
cfg = [];
cfg.parameter = 'avg';
cfg.xlim = [0.35 0.35];
cfg.channel = data.label;
cfg.layout = layout;
cfg.marker = 'labels';
cfg.zlim = [-3 3];
cfg.style = 'straight';
cfg.colormap = '*RdBu';
cfg.shading = 'interp';
cfg.gridscale = 300;
figure; ft_topoplotER(cfg, data);

I have scaled the layout to prevent all electrodes from clustering at the
center of the brain. This adjustment has allowed for a more accurate
representation of electrode positions relative to the brain. However, the
electrodes located outside the brain contour do not display their values.

So I am seeking advice on the following points:

Is there a way to modify the cfg parameters or adjust the layout in
FieldTrip to enable the visualization of electrode colors outside the brain
contour on the topographical map? If direct cfg adjustments within
ft_topoplotER are not feasible, how should I alter the layout variable for
this purpose?

Thank you in advance for your time and assistance.

Best regards,

Chengyuan Wu
Ningbo Kangning Hospital
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