analysis name: frequency tagging?

[kalenkovich]

@dominikwelke, I read your conversation with Rob Luke about what the analysis/method/phenomenon name should be: frequency tagging, steady-state response, etc. (don't want to link the mne-python issue to avoid spamming everyone with "this issue has been mentioned").

My personal preference (see the repo/package name 😃) is frequency tagging. The reason is that it is modality-neutral in the literature. My light googling showed that the auditory people prefer ASSR (auditory steady-state response) while the visual people mostly use VSSEP (visual steady-state evoked potential). Obviously, the common denominator is the steady-state part but steady-state what? Response implies some external stimulus (I strongly disagree on this with Rob Luke when he said that frequency tagging implied an external stimulus while ASSR did not, I think it is the opposite). So does evoked in evoked potential. Then we can just use potential but that excludes the MEG people. Which might not be a problem: I think no one ever was really confused by the use ERP when what was meant was ERF (I was confused by ERF though).

I am not sure who coined the "frequency tagging" term. The earliest use I could find was in this 2009 paper by Marco Buiatti et al. Here is a post by Dr. Buiatti called "frequency tagging".

And just to add my personal understanding of the term: a specific frequency tags an external stimulus (think SSVEP) or an endogenous (think tinnitus frequency example from Rob).

Here is a list of names used with pros and cons (feel free to update it!):

Name	Pro	Con	Ref with usage
frequency-tagging	modality-neutral no stimulation implied	unfamiliar to users	Marco Buiatti et al., 2009
ASSR	well-established	modality-specific stimulation implied	lots and lots
VSSEP	well-established	modality-specific stimulation implied	lots and lots
FVPS	intuitive	modality-specific stimulation implied very specific stimulation implied easily confusable with related RSVP	Stothart et al., 2020

[dominikwelke]

yea, fortunately we agree on that :)
thanks for the nice table: will add entries if i see something else

i was actually surprised, how strongly Rob seemed to feel on this, but i dont think i will enter a fight on this.

"steady-state activity" could be another option that comes without "response" or "potential vs. field" ballast.

but as i already mentioned / tried to convey in the mne issue I am less happy with the "steady-state" part.
yes, in the logic of our analysis its a steady signal (meaning we assume it steady after a transient phase to be able to do the anaylsis we do), but the brain doesnt do anything steady - i guess in assr its something like a dynamic tracking of the stimulus envelope, and in ssvep something like a series of VEPs, that manifests as a peak in the fft spectrum.
further on ppl showed effects of directed attention: hence, if ppl shift attention to or from a assr/ssvep stimulus during a trial the strength of the response should change dynamically (which we dont see, of course, doing an fft over the whole trial)

however, i do agree with Rob that frequency tagging (at least intuitively) implies a researchers manipulation. but this doesnt bother me, since this is what usually happens in studies. i couldnt think of many possible endogenous sources (only tinnitus, or maybe some very esoteric things like hypothesizing harmonic responses to our individual alpha :D ).
and then, similar to what you said, its always possible to turn it around and say "the EEG has a frequency tag, who cares whether it's a syntetic or a 'natural' source that induces it?"

speaking of tinnitus: I'm not even sure if this is a good example... if it is a high pitch pure tone / sine in the range of several khz you cannot actually see it in the eeg, right? unless one samles with 10 khz :D
a superficial lit search showed me that tinnitus seems to be able to enhance ASSR, though.

[kalenkovich]

Ok, let's just stick to "frequency tagging" for now then.

[dominikwelke]

sure, i thought we had discussed this a bit before but maybe i mix things up :)