Topolots for each band of frequencies

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HI ,
Is there a way to generate topoplots for only a particular frequency band
of ERP data? I would like to generate topoplots for each frequency band
separately to visualize alpha / delta / beta bands activations in the
topoplots . As of now am able to generate a generic topoplots with mne
libraries. Would like to tweak this to make it frequency band specific.
Any help here appreciated.

Regards,
Sundar.
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Hi,

The following link might be helpful:

https://martinos.org/mne/stable/auto_tutorials/plot_sensors_time_frequency.html

-Mary

3

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Thanks Mary,
This is very helpful, however can i do the same with evoked data, as i have
non - epoched eeg data .
This is in csv format with just channel numbers .

Regards,
Sundar.

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Hi Sundar,
Unfortunately the plot_topomap method of Evoked objects does not have the
`bands` argument like the Epochs.plot_psd_topo method does.

I think the general approach would be:
1. read in your evoked data from CSV format into a NumPy array
2. use mne.EvokedArray()
<https://mne-tools.github.io/dev/generated/mne.EvokedArray.html> to convert
it to an MNE Evoked object
3. use Evoked.filter()
<https://mne-tools.github.io/dev/generated/mne.Evoked.html?highlight=evoked%20filter#mne.Evoked.filter>
method to isolate the frequency band
4. use Evoked.plot_topomap
<file:///opt/mne-python/doc/_build/html/generated/mne.Evoked.html#mne.Evoked.plot_topomap>
method to plot (see this tutorial
<https://mne-tools.github.io/dev/auto_examples/visualization/plot_evoked_topomap.html>
for examples)

5

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You could also turn the Evoked object into an Epochs object using
EpochsArray

epo = EpochsArray(evoked.data[np.newaxis], evoked.info)

And then you could probably use the epoch-based plotter.

Eric

6

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Thanks Dan and Eric,
They were some very helpful suggestions.

Now i have them working with band specific topoplots.
I am trying to animate the sequence with topoplots like a movie , here i
am hit with the issue of refresh rate where in the animation is not smooth.
Could be because of the text output from the function.

plot= epochs.plot_psd_topomap(ch_type='eeg', normalize=True,verbose=False)
plot=evoked.plot_topomap(
ch_type='eeg',times=times,sensors=False,show_names=True, title='Alpha')

how do i disable this text output and retain only the plots. This could
help in smoother animated plot with matplotlib functions.

Regards,
Sundar.

7

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Sundar, Have you looked at Evoked.animate_topomap
<https://mne-tools.github.io/dev/generated/mne.Evoked.html#mne.Evoked.animate_topomap>
?