[Eeglablist] epoch length inquiry for short trials

[Kavanaugh, Brian]

Great, thank you Makoto!

On Wed, Jan 12, 2022 at 11:04 AM Makoto Miyakoshi via eeglablist <
eeglablist at sccn.ucsd.edu> wrote:

> Dear Brian,
>
> I agree with Scott.
> Wavelet transform/STFT uses a sliding window. If your default 3-cycle at
> 3-Hz (1116 ms long) window is applied to produce ERSP/ITC data for every 4
> ms (assuming 250 Hz sampling), each sliding window is 1112 ms overlapped
> with the adjacent one! So the outcome is already very redundant in that way
> so no worry about another redundancy. You don't lose anything except for
> the computational time, and you are not biasing the data in any
> particular direction. There is no problem if redundancy is not a sin in the
> given situation!
>
> Makoto
>
> On Mon, Jan 3, 2022 at 7:15 AM Kavanaugh, Brian via eeglablist <
> eeglablist at sccn.ucsd.edu> wrote:
>
> > Hi Scott,
> >
> > Wonderful, thank you for your guidance!
> >
> > Brian
> >
> > On Mon, Jan 3, 2022 at 12:06 AM Scott Makeig <smakeig at gmail.com> wrote:
> >
> > > Brian -
> > >
> > > There is no problem with extracting overlapping epochs if you keep in
> > mind
> > > which parts overlap.  If you are interested in measures in the
> > > time/frequency domain (ERSP, ITC, coherence and cross-coherence, etc.),
> > > then it is necessary to use a long enough trial epoch to include, e.g.,
> > at
> > > least one time window wholly within the trial 'baseline' period before
> > the
> > > first latency of analysis interest (to enable within-trial
> > > before/during/after comparisons), and at least one window centered at
> the
> > > last latency of analysis interest. To measure down to 3 Hz - using a
> > > 3-cycle window to improve spectral resolution - a -1-s to 2-s window
> > length
> > > is sufficient.
> > >
> > > Scott Makeig
> > >
> > > On Sun, Jan 2, 2022 at 11:55 PM Kavanaugh, Brian via eeglablist <
> > > eeglablist at sccn.ucsd.edu> wrote:
> > >
> > >> Hi everyone,
> > >>
> > >> Our kids go/nogo task has shorter trials (500 ms stimuli, 900 ms
> > response
> > >> window [or until response], 200 ms inter-trial interval) than the -1
> to
> > 2
> > >> second epoch time length. Particularly as we are interested in midline
> > >> theta activity.
> > >>
> > >> I'm sure this has been explained before, but I struggled to find it in
> > the
> > >> archives. I apologize in advance.
> > >>
> > >> If I use the -1 to 2 sec epoch in eeglab, won't these epochs overlap
> > >> trials? Making inter-trial intervals longer would seem to solve this
> > >> issue,
> > >> but now that data has been collected... Any advice on optimal
> epoching?
> > >>
> > >> Thank you!!!
> > >>
> > >> Brian
> > >>
> > >>
> > >> Brian Kavanaugh, Psy.D., ABPP
> > >>
> > >> Board Certified in Clinical Neuropsychology, Pediatric Subspecialist
> > >>
> > >> Pediatric Neuropsychologist, E. P. Bradley Hospital
> > >>
> > >> Assistant Professor (Research), Warren Alpert Medical School of Brown
> > >> University
> > >> _______________________________________________
> > >> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
> > >> To unsubscribe, send an empty email to
> > >> eeglablist-unsubscribe at sccn.ucsd.edu
> > >> For digest mode, send an email with the subject "set digest mime" to
> > >> eeglablist-request at sccn.ucsd.edu
> > >>
> > >
> > >
> > > --
> > > Scott Makeig, Research Scientist and Director, Swartz Center for
> > > Computational Neuroscience, Institute for Neural Computation,
> University
> > of
> > > California San Diego, La Jolla CA 92093-0559,
> > http://sccn.ucsd.edu/~scott
> > >
> > _______________________________________________
> > Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
> > To unsubscribe, send an empty email to
> > eeglablist-unsubscribe at sccn.ucsd.edu
> > For digest mode, send an email with the subject "set digest mime" to
> > eeglablist-request at sccn.ucsd.edu
> >
> _______________________________________________
> Eeglablist page: http://sccn.ucsd.edu/eeglab/eeglabmail.html
> To unsubscribe, send an empty email to
> eeglablist-unsubscribe at sccn.ucsd.edu
> For digest mode, send an email with the subject "set digest mime" to
> eeglablist-request at sccn.ucsd.edu
>