I would like to know which is the best way to calculate the difference waves in the oddball paradigm?
The original oddball difference wave seems to be just a direct subtraction of the EEG values of the deviant and standard stimuli, and the code implementation of mne seems to be different from this?
I have some confusion about the principle and results of combine evoke.
If I get the standard stimulus minus the abnormal stimulus to produce a differential stimulus result (oddball paradigm).
The function provided by mne seems to be the combine evoke function.
But shouldn’t the total number of evokes be the same?
For example, if I have 100 standard stimuli and 100 abnormal stimuli, then
odd = mne.combine.evoked([std,dev],weights=[-1,1])
After that, shouldn’t there be 100 different stimuli?
But it seems that both mne’s own sample code and the one I came up with halve the number of stimuli.
And I’m curious what the difference is between these two codes? Why does the generated evoke have a different nave?
(dev_all evoke number =130 std_all evoke number = 130)
odd_all = mne.combine_d([dev_all, std_all], weights=[1, -1])
odd_all = mne.combine_d([dev_all, -std_all], weights=‘equal’)