Hello everyone,
I try to do time-frequency analysis on the EEG data which are processed.
I want to average the trials together within a condition and then average the data within a group before doing the frequency treatments.
The problem is that I cannot average across participants in a group as they do not have the same channel numbers (some channels were removed during the pre-processing).
I have tried to interpolate each of my EEG structures with the interpol.m (Marco Simoes) function which takes as input an EEG structure and a chanlocs - cell array of channels specification (taken from EEG.chanlocs before removing channels) and returns as output an EEG structure with the new electrodes and respective signal added in he right places but I get this type of error: unable to perform assignement because the size of the left size is 70x45500 and the size of the right size is 61x45500.
I don't see how to solve this problem as I want all my structures to have 61 channels so that I can compare the data between participants.
Thank you very much for your help.
Best regards,
Mohamed Bouguerra
The FieldTrip Toolbox in Matlab (which you appear to be using) has some great tutorials on how to preprocess EEG data, which includes electrode interpolation. One example is here: https://www.fieldtriptoolbox.org/workshop/madrid2019/tutorial_cleaning/#interpolating-bad-channels
Also your error seems like something that can be produced if you try to reduce the channels with the interpolation function. If I had to guess, you have data that has 70 channels and you tried to use the interpolation function with the position locations of the 61 channels that all subjects had in their data. The reverse should be done if this is the case.
Thanks for your responses.
I tried to complete the missing electrodes at 61 to have the same number of electrodes for each subject. Indeed I do not understand why the number 70 appears. I have the same error message with 46 channels for example.
The problem is that when I apply the Interpol.m function to an EEG structure with, for example, 50 channels (indicating a chanloc of 61 electrodes), I get a structure with more electrodes than 61.
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