- MNE-Python version: 0.21.2
- WSL Ubuntu:

The objective is to compute the spectral connectivity measures for each of the epoch as discussed here. Along the pipeline, the list of epochs will be croped in between `x`

duration and each epoch will be extracted and feed separately into the `spectral_connectivity`

module. For example, the epochs will trimed between `tmin=-60`

and `tmax=-56`

. For the sake of the discussion, let us calculate the `spectral_connectivity`

of the epoch with index `0`

as shown per the code snippet below.

```
import mne
from mne.connectivity import spectral_connectivity
# method=['coh', 'plv', 'ciplv', 'ppc', 'pli', 'pli2_unbiased', 'wpli', 'wpli2_debiased']
method=['coh']
epochs = mne.read_epochs ( 'raw_csd-epo.fif', preload=True )
epochs = epochs ['Road edge excursion']
sfreq = epochs.info ['sfreq']
epochs.baseline = None
epoch_win_t = epochs.copy ().crop ( tmin=-60, tmax=-56, include_tmax=True )
epoch_win =epoch_win_t[0]
# epoch_win=epoch_win_t
con, freqs, times, n_epochs, n_tapers=spectral_connectivity ( epoch_win, method=method,mode='fourier', sfreq=sfreq, faverage=True, mt_adaptive=False, n_jobs=-1,fmin=[4], fmax=[8])
```

The above code snippet will produce an all `1`

connectivity between the channel as shown in the figure below.

Similarly, the same output was produced for epoch_win_t[1] and epoch_win_t[2], which correspond to the second and third epoch, respectively. In addition, experimenting with different `method`

also produced the value `1`

.

However, when feeding all the epoch altogether into the `spectral_connectivity`

module, by setting the ` epoch_win=epoch_win_t`

would produced the following output.

If I understand correctly, the above output is the average connectivity for all the 3 epochs.

However, as seen at the first figure, the connectivity at the lower triangle is equal to ONE, and this also happen to be true for the second and third epoch. I we average these three epochs manually, the result should be equal to 1 for all the lower triangle.

I really appreciate if someone can shed some light on where did I do wrong?

The raw_csd-epo.fif can be downloaded via the link: https://drive.google.com/file/d/1Z4cWjAMdwGH-p56p6SpkGNKlINVKYjg0/view?usp=sharing