My EEG topographic map is like this, how should I solve it？

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1

MNE-Python version:0.23.4
operating system:windows10
This is an EEG topographic map generated by mne on my computer, but it is not normal

code:
raw = raw.filter(l_freq=0.1, h_freq=30,fir_design=‘firwin’)
raw.plot_sensors(ch_type=‘eeg’, show_names=True)

pic:
image

2

Hello @Kirito and welcome to the forum!

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Best wishes,
Richard

3

I would additionally advice to look at the time series for ICA

It looks like ICA024 could be ocular artifacts but best to confirm by looking at the time series

You seem to have a scaling issue in the topomap too. Take a look at “sphere” argument in plot_topomap:

https://mne.tools/stable/generated/mne.viz.plot_evoked_topomap.html

You can pass it via topomap_args

Hope that helps.
Mainak

4

@Kirito By not normal I assume you mean - the channels are far away from head circle. If so, take a look at the following thread:

you can also try manipulating the sphere argument to see how that changes the channel layout. See this tutorial to better understand what sphere argument does and how to use it:
https://mne.tools/dev/auto_tutorials/intro/40_sensor_locations.html#controlling-channel-projection-mne-vs-eeglab

5

Shouldn’t we assume that there’s something wrong with the montage first before suggesting to fiddle with those plotting parameters? MNE should normally plot everything correctly without such manual interventions …

6

I think there’s something wrong with the montage, because I carefully compared the data and found that ch_channels has two more channels, CB1 and CB2. But I don’t know how to solve this problem.

7

Indeed, I see these channels now that I look at the topomap carefully. Are they EEG channels? If not, you should mark them appropriately using raw.set_channel_types and that should fix your problem

Mainak

8

I think these are mastoid channels, they probably shouldn’t have a location set or be dropped after referencing, like @mainakjas suggested.