A recent question from @tinnire initially said,
"PS. Someone add a tag for MEG (magnetoencephalography) please."
I created meg, but haven't filled out the tag wiki yet, and @ArtemKaznatcheev added neurobiology instead of meg to tinnire's question. If meg is undesirable, vote this answer down and consider removing the dedicated tag or adding it as a synonym for one of the broader tags. Otherwise, if it gets voted up, I'll fill in the tag wiki if no one else does (I have no experience with or real knowledge of MEG). I wouldn't recommend eeg as a synonym, but the broader neuroimaging would work if a tag that is more specific is not useful. At present, a search for "MEG" produces eight results, but these are mostly answers, not OPs that mention MEG specifically.