[Eeglablist] Data reduction after extracting epochs

[Mastaneh Torkamani]

Dear Makoto,

The units I had defined in the text file and custom scripts were correct. I
think the problem was caused by the large baseline latency range (-1000 0)
which had replaced the original epoched dataset. When I reduced this range,
I could easily get the desired ERP plots.

Thanks for your help,

Mastaneh


>
> From: Makoto Miyakoshi <mmiyakoshi at ucsd.edu>
> To: Mastaneh Torkamani <mastaneht.83 at gmail.com>
> Cc: EEGLAB List <eeglablist at sccn.ucsd.edu>
> Date: Mon, 15 Jul 2013 18:26:31 -0700
> Subject: Re: [Eeglablist] Data reduction after extracting epochs
> Dear Mastaneh,
>
> Please check if you by any chance confused time units (seconds vs.
> datapoints).
>
> Makoto
>
>
> 2013/7/13 Mastaneh Torkamani <mastaneht.83 at gmail.com>
>
>>
>> Dear all,
>>
>> I have a number of EDF files which contain recordings from an epithetic
>> patient. As the IPS and HV events were not correctly saved in those files,
>> I added the event information to a text file and wrote a script to load all
>> the fields into the EEG structure. I followed instructions in this link
>> http://sccn.ucsd.edu/wiki/Chapter_03:_Event_Processing and believe the
>> event fields and values are similar to the example data sets and match.
>> However, when I extract epochs, the data length is considerably decreased
>> and all the events seem to overlap with each other. Therefore, I cannot get
>> any ERP plots and receive the following info :
>>
>> Removing 20 trials with NaN sortvar values.
>> Setting variable avewidth to max 2.
>> Sorting data on input sortvar.
>> 100.00% of the trials (i.e., 2 out of 2) have the same sortvar value as
>> at least one other trial.
>> Distribution of number ties per unique value of sortvar:
>> Min: 2, 25th ptile: 2, Median: 2, 75th ptile: 2, Max: 2
>> Smoothing the sorted epochs with a 2-epoch moving window.
>>   and a decimation factor of 1
>>
>> So, what should I do to define the trials and epoch lengths correctly?
>>
>> Any help is greatly appreciated.
>>
>> Best,
>> Mastaneh
>>
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>
>
>
> --
> Makoto Miyakoshi
> Swartz Center for Computational Neuroscience
> Institute for Neural Computation, University of California San Diego
>
>
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