This is generating random data following a normal distribution. It’s useful to debug a program, but does not mimic any form of brain signals. The method you tried in the post Has anyone tried generating EEG signals using MNE library? where @cbrnr suggested this tutorial Simulate raw data using subject anatomy — MNE 1.8.0 documentation will create fake sensor data by taking into acount:
- the position of the sources of neural activity
- the head anatomy
This information is contained in the forward model (specifically in the source space attached).
This method is more complex, but it does generate a simulated sensor signal, EEG or MEG.
Mathieu