[Eeglablist] Electrode layout for dipole source localization

[Malte Anders]

Dear all,

I want to carry out dipole source localization for ICs that - on average -
have the following scalp activation pattern:
https://urldefense.com/v3/__https://imgur.com/USk8CGA__;!!Mih3wA!X4GEC2erOHRizWwT6HNR1LRz8O8nXJ4GOt1Ore6--nwEGYV9MC-OgW4PsGzR3Tsejnhoiw$ 

On the linked image, dipfit results weren't so good, probably due to the
fact that I used only 17 electrodes. The dipole is however located
somewhere beneath the Cz electrode, facing upwards, as one can imagine by
looking at the image.

I have around ~54 active electrodes available that I can use, with limited
budget to order new ones. If I want to improve the results in a future test
setup, should I:
Option 1: evenly concentrate the additional available electrodes around the
Cz electrode (C1, C2, C3, C4, FC1, FCz, FC2, CPZ, CP1, CP2 etc.) so that
most of my electrodes will pick up the signal from my dipole of interest
Option 2: evenly distribute the electrodes around the whole head,
regardless of the fact that they will probably not pick up the signal I am
interested in?

Option 1 seems the logical answer, but I am concerned that if I go for that
option and apply average reference on my datasets afterwards, ICA
performance will suffer as this will reduce my overall EP amplitude (more
electrodes picking up the signal) and ICA will not be able to identify the
independent components anymore. Thus, I have a slight feeling that Option 1
could introduce a bias into my data as I will probably cluster my
components according to their ERP properties (in a blinded fashion) and not
cluster according to dipole location.

Any help is appreciated!

Best,
Malte