[Eeglablist] P300 Analysis in STUDY

[Tarik S Bel-Bahar]

>
> Hi Joseph, some quick responses below, good luck!​
>
>
>
>
>
> *************RESPONSE FOR JOSEPH************************
> ********************************
> first ​
> see the following on google scholar
> ​ which provides plenty of general guidelines related to your question.​
>
>
> Event-related potentials in clinical research: guidelines for eliciting,
> recording, and quantifying mismatch negativity, P300, and N400
>
> Be sure to ​also review about ~20 recent publications from respected
> authors using P3 measures in high-impact journals for general guidelines.
> You may also want to examine reviews about different subcomponents of the
> P3, such as P3a, P3b, etc... all easy to find on google scholar
>
>
> THEN....
>
> 1a. It depends on what your ERP looks like. You should review major
> methods for computing ERP metrics from various handbooks for ERP/EEG such
> as the ones from Luck or Handy. See also online tutorials from Luck for
> ERPLAB that cover various ERP metrics. See also methods in the research
> articles that you are trying to emulate. You should be able to find at
> least 20 or 30 articles on Google Scholar, each of which will describe how
> they computed their P3 ERP metrics.
>
> 1b. Use time windows based on published research that has used similar
> paradigms as yours.
> Also pick time windows based on what you see in your grand-average ERPs
> and your single-subject ERPs (the latter will be more variable of course).
>
>
> 1c.​ Yes usually/often midline at frontal, central and central-posterior
> sites (but depends on a variety of factors).
> Refer to reviews (such as from Polich or others) on the P3. I think it
> depends on the particular protocol, type of stimuli, type of population.
> Reviewing 10 to 20 recent articles (or classic articles) will give you a
> good enough idea of where to expect P300 dynamics for your paradigm.
> Anyway, if you just type "p300 EEG topomap" into google images, you can
> get a good idea of the scalp distribution of p300.
>
>
> ​1d. Get the the time series from the data for a particular channel or
> group of channels. Determine what part of that time series is your time
> window of interest. Then average up that data within the time window. You
> would do so by isolating the timewindow for that channel(s) into a matrix
> of data, and then taking the average via a matlab function. Of course,
> please familiarize yourself (Point 1a above) with the various ways to
> compute ERP metrics.Note also your data should likely be appropriately
> baselined, etc...
>
> 2. See Luck's and ERPLAB's pages on that measure.
> Just google "half area latency eeglab" and there are several useful links
> and examples.
> The blog page that comes up as one of the first links, by Lindeløv, seems
> kind of useful for your case, which should be translatable to study metrics.
> Also google "eeglablist and your topic" for some other past eeglablist
> discussion related to your topic.
>







On Mon, Sep 25, 2017 at 6:53 AM, Joseph Nuamah <jknuamah at aggies.ncat.edu>
wrote:

> Dear All,
>
> In my STUDY design, there are two conditions. I want to, among other
> things, determine whether the difference between P300 amplitude and latency
> for both conditions is statistically significant.
>
> Please find my questions below:
> 1a. Given that P300 is a broad component, how do I derive temporal windows
> for analysis ?
> 1b. In particular, what time after stimulus onset should that be applied
> to?
> 1c. Will that vary across channels (I intend to use  midline sites Fz, Cz,
> and Pz)?
> 1d. How do I average amplitudes within these temporal windows for each
> participant ?
>
> For say channel PZ, I am able to retrieve erpdata and erptimes from
> [STUDY erpdata erptimes] = std_erpplot(STUDY,ALLEEG,'channels',{ 'PZ'});
> I read about fractional-area (50%) latency in the literature.
>
> 2. Can I determine half-area latency with corresponding amplitude for P300
> in STUDY?
>
> Kindly help.
>
> Thanks!
>
> Joseph
>
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