While inspecting the EEG power spectral density from one subject, I got this super weird pattern. I searched everywhere but still cannot figure out what is happening here. I was wondering if it is related to the filters I used - I applied [0.1Hz,80Hz] band-pass filters to the data of every subject - but only this subject showed this weird pattern. If you have any idea what might be causing this, I will be more than glad to hear! Thank you!
A weird oscillatory noise on the ref electrode, spread to other electrodes by common average reference maybe? It’s difficult to say more without seeing the data. Could you share the file with the provider of your choice?
Without having checked out the file, this PSD pattern usually occurs because of a large artifact (spike, overflow) in your data (the oscillatory-like behavior can also be due to aliasing). I’d check the affected data sets, and if they contain such large artifacts mark them with “BAD”.