Hi,
I use brainstorm (forward model) to simulate ear-EEG data.
In order to get a representation that is comparable to my actual ear-EEG recording, I have to re-reference with signal, i.e. I subtract the signal of the reference-electrode position from all other channels.
What is not clear to me yet for this forward model is the role of the DRL (driven right leg, of the amplifier). Do I have to account for that as well? In my setup DRL, REF and recording electrodes are all in close poximity to each other.
Thanks
Martin
I am sorry but I don't know what a DRL is and what it does. Would you mind clarifying, please?
I would expect that only the REF electrode need to be taken into account in the forward model. You can also elect to re-reference your recordings to AVG (average reference) - this is possible in Brainstorm. The forward model will also then be expressed with respect to an AVG electrical reference and you will not need to worry about the exact location of the REF electrode anymore.
That said, in teh case of ear-EEG where electrodes are all packed around similar locations, the AVG reference may end up removing a lot of signal of interest depending on the gradient of brain signals of interest across electrodes. You will need to give it a try and validate e.g., by measuring the event-related response to a simple sensory event for instance.