How to average the epoch data of different subjects

đź’¬ Support & Discussions
1

I want to ask if there is a way to average the epoch data of different subjects. I want to do group data analysis.
I have watched mne.grand_average(mne.grand_average — MNE 0.22.0 documentation)
But this seems to only merge evoke data, and I want to merge epoch data because there are multiple metadata in my epoch data. If the epoch is merged, I only need to merge one epoch of each subject. If I merge evoke data, I need to combine more than a dozen evoke data from each participant.

Thank you very much for your help and look forward to your reply!

2

I don’t understand your use case. Could you elaborate in more detail what you are trying to achieve?

Grand-averaging epochs across participants is typically not possible because epochs counts might be different; and noise levels might be different too, so you should generally average epochs within each participant first.

3

I calculated the epoch data of each subject and the evoke data under each condition. I want to use the averaged data of all subjects to draw a topo plot or other plot.
I want to ask if I can directly merge or average the epoch data of all subjects to get the group average epoch data because I have too many evoke data, if I can merge the epoch data, I can use the merged epoch data to generate different conditions evoke data.
I mainly want to plot the data after the group average.

4

If you want to have an average across all conditions, simply create a single Evoked per participant across those conditions, and then use mne.grand_average() to calculate the grand average across participants.

5

I understand, mne does not use epoch to average data.
Thank you very much for your reply, then I will create evoke files separately for averaging.