Hi folks,
I have a dataset (Localize-MI) that uses EGI-256. I need to drop channels in a principled way to check my reconstruction error of missing channels (eg EGI-128, 64, etc.) but MNE, among other sources, only seems to return one version of EGI, EGI-256. I supposed that Hydrocel is the same montage since EGI manufactures the system, but the raw coordinates (and even after normalization) are not one-to-one. They look quite different along the -Z direction. Are Hydrocel and EGI supposed to be the same montage? Where can I get the EGI-128, 64, etc. montage coordinates? Any resources here would be greatly appreciated here.
Yeah it is my understanding that ‘GSN-HydroCel-128’, ‘GSN-HydroCel-129’, ‘GSN-HydroCel-256’ are all meant to be idealized montages for EGI nets. As to why the‘GSN-HydroCel-256’ and `EGI_256` coordinates are not 1:1 I am not sure.. I wasn’t around when either of those template montages were added.
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Just a heads up for anybody else wondering this: EGI-256 is the old montage setup (‘GSN’) from the company EGI. They have not produced this machine for over two decades.
For most datasets you will see nowadays, you will almost always want to use the Hydrocel-256 (‘H-GSN’) montage instead. Many papers will write “EGI montage” and this is technically correct because it’s the same company, but I found this confusing. They are not the same
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Thank you for the reply! I got an explanation from EGI, added it to the thread
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