[Eeglablist] about a blinking period in an EEG protocol

[Makoto Miyakoshi]

Dear Jose,

> I'm aware of the several methods to correct these artefacts. Also, I'm
aware that the mental effort involved in suppressing eye blinks may impair
task performance, and this can be even more pertinent when we deal with
psychiatric subjects (a simple task can become a double task).

That's great to start with.

> However, could be this be an issue in a purely visual task? because when
a subject blinks during the stimulus display she/he is simply not seeing
the stimulus (or at least not seeing the way it could see it when is not
blinking). Couldn't be better to have a blinking period?

If you have a separate blink period during which subjects may blink, then
subjects must control the blink behavior accordingly, which occupies one of
the cognitive slots for the top-down control on behavior; this introduces a
dual-task.

> Also, even if we remove artefactual activity from the data, I wonder if
blinking could have an effect on the cognitive process we want to measure,

I've seen papers reporting that blinking is related to attention, and I
know that blink is also related to dopamine system. If this is true, it
means there is temporal correlation between experimental events and blinks.

I think that let subjects blink freely during the experiment (i.e. release
the cognitive slot) and use ICA as a post-process is the best solution to
deal with eye blink artifact. Some people used to say that the process of
IC selection is arbitrary, but now there are multiple toolboxes available
for that purpose. It may not be a too bad idea to try out these EEGLAB
toolboxes. See also http://sccn.ucsd.edu/wiki/Std_selectICsByCluster

Makoto

On Wed, Jun 24, 2015 at 3:24 PM, José Luis <joseluisulloafulgeri at gmail.com>
wrote:

> Hello,
>
> I’m working at the Clinical Research Unit in the Ville-Evrard Hospital in
> France. We are planning to perform EEG studies in psychiatric subjects. In
> this context, we would like to do classical experiments such as oddball,
> stroop and lexical decision.
>
> Looking the literature on ERP studies, I realise that often these
> paradigms do not include a "blinking" period, i.e., a period where one
> explicitly ask the participant to perform eye movements (blinking or
> saccades). I'm aware of the several methods to correct these artefacts.
> Also, I'm aware that the mental effort involved in suppressing eye blinks
> may impair task performance, and this can be even more pertinent when we
> deal with psychiatric subjects (a simple task can become a double task).
> However, could be this be an issue in a purely visual task? because when a
> subject blinks during the stimulus display she/he is simply not seeing the
> stimulus (or at least not seeing the way it could see it when is not
> blinking). Couldn't be better to have a blinking period? Also, even if we
> remove artefactual activity from the data, I wonder if blinking could have
> an effect on the cognitive process we want to measure,
>
> Any comment will be appreciated,
> José Luis
>
> --
> José Luis ULLOA FULGERI, PhD
> https://sites.google.com/site/joseluisulloafulgeri/
> 33 (0)6.29.50.64.93
>
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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