[Eeglablist] ERSP outputs

[Makoto Miyakoshi]

Dear Erika and John,

Sorry for the trouble. John's viewpoint is absolutely correct. The fact
that you got 183 timepoints though you specified 200 time points may
indicate it could not generate 200 time points because of the sliding
window size you specified. Another possibility is that you made a mistake
in entering optional inputs so that some/all of them were not recognized
properly (but I doubt this though, since EEGLAB input check is usually
quite strict, but there are exceptions and unexpected errors so no
guarantee).

General advice is that you try one optional input at a time and run the
test run. Add a new option one by one, so that you can identify which
optional input dose not behave well.

Makoto



On Thu, Jul 18, 2019 at 11:28 AM Johnson, John T. <john.johnson at gatech.edu>
wrote:

> In my experience (much less than Makoto, et al.), the parameters you
> provide are treated as requests. The time and frequency ranges actually
> used are based on your data. Things such as the sampling rate can affect
> the number of frequencies generated. Time can be altered by the filtering
> method used (Hanning, etc.), number of cycles specified, etc. If I were
> troubleshooting this, I would set a breakpoint in std_ersp.m at line 347
> which is the call to newtimef(). The newtimef() call actually does the work
> of calculating the time-frequency information. From there, you can inspect
> the variables being passed to newtimef() and see if window size,
> multi-taper, etc. are affecting your results. If this doesn’t provide
> answers, you might need to dig into newtimef.m itself to see how the
> parameters are modified before the calculations are performed. E.g. set a
> breakpoint at 878 and inspect the parameters in the g struct.
>
> Regards,
> John
>
> On 16 Jul 2019, at 15:44, Erika Nyhus wrote:
>
> Hi Makoto,
>
>
> I am confused because when I run std_precomp it says the output
> frequencies are 3-125 Hz, 100 frequencies and the time range is -240-1440,
> 200 timepoints, but when I look at the ersp data after plotting the output
> frequencies are from 3-49 Hz, 75 frequencies and the time range is
> -100-1440, 183 timepoints.
>
>
> Erika Nyhus, Ph.D.
> Department of Psychology and Program in Neuroscience
>
> 6900 College Station
> Bowdoin College
> Brunswick, ME 04011
> ________________________________
> From: Makoto Miyakoshi <mmiyakoshi at ucsd.edu>
> Sent: Friday, July 12, 2019 11:57:55 PM
> To: Erika Nyhus
> Cc: EEGLAB List
> Subject: Re: ERSP outputs
>
> Dear Erika,
>
> Basic facts about the parameters can be found here.
>
> https://sccn.ucsd.edu/mediawiki/images/a/a6/C2_A3_Time-frequencyDecAndAdvancedICAPracticum_updateJan2017.pdf
> <
> https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsccn.ucsd.edu%2Fmediawiki%2Fimages%2Fa%2Fa6%2FC2_A3_Time-frequencyDecAndAdvancedICAPracticum_updateJan2017.pdf&data=02%7C01%7Cenyhus%40bowdoin.edu%7Cb8d6248ec2074b17355908d707466229%7C984e32e5f98a4600aa3227c3f948abe3%7C1%7C1%7C636985871232653522&sdata=aqeS9fx60AYuJ0445EnbfuYOYSTjdOH9QS5YDYapCjY%3D&reserved=0
> >
>
> However, 'nfreqs', 100 generated 75 frequencies does not make sense. Are
> you sure 'nfreqs' was properly recognized when you performed the
> calculation? I have never heard of it.
>
> Makoto
>
> On Thu, Jul 11, 2019 at 11:04 AM Erika Nyhus <enyhus at bowdoin.edu<
> mailto:enyhus at bowdoin.edu <enyhus at bowdoin.edu>>> wrote:
>
> I am confused about the outputs for ERSPs in std_precomp. My data was
> epoch from -800-2000 ms and the only inputs I set for erspparams was
> 'cycles' [3 .8], 'nfreqs' 100, 'ntimesout' 200. I am not sure why the
> output frequencies are from 3-49 Hz, 75 frequencies and why the time range
> is -100-1440, 183 timepoints.
>
>
> Erika Nyhus, Ph.D.
> Department of Psychology and Program in Neuroscience
>
> 6900 College Station
> Bowdoin College
> Brunswick, ME 04011
>
>
> --
> Makoto Miyakoshi
> Assistant Project Scientist, Swartz Center for Computational Neuroscience
> Institute for Neural Computation, University of California San Diego
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>
> John T. Johnson
> PhD Candidate - Cognitive Motor Control Laboratory
> Lab TA NEURO 2001 Principles
> School of Biological Sciences
> Georgia Institute of Technology
>
> 678-575-2093
> john.johnson at gatech.edu
>


-- 
Makoto Miyakoshi
Assistant Project Scientist, Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego