[Eeglablist] re-epoching, ICA selected periods

José Luis joseluisulloafulgeri at gmail.com
Sat Mar 4 15:48:46 PST 2017

I'm sorry my question was not enough clear,
I don't need to add another marker based on two previous markers. I need to
epoch my data based in two markers because my period of interest is between
a given marker A and another marker C and this interval of time is variable,
I have tried to found other related threads in the EEGlab list but the last
one was on 2013, and apparently there was no way to do it, I wanted to know
if someone has implemented this by now,


On 5 March 2017 at 00:02, Tarik S Bel-Bahar <tarikbelbahar at gmail.com> wrote:

> Hello Jose, yes use addnewevents ? function mentioned in eeglablist.Use a
> matlab loop to make a new list of events based on the events you have
> already. Then epoch on the new events you've made.
> also several past eeglablist emails exist about making lists of new events
> and importing them
> On Sat, Mar 4, 2017 at 4:54 PM, José Luis <joseluisulloafulgeri at gmail.com>
> wrote:
>> Hi Tarik,
>> Thanks for the input,
>> Looks the approach we are taking is good,
>> However, I haven't be able to epoch using two triggers, I need to select
>> an epoch which is 0.5 sec before a trigger A, and 0.5 sec after a trigger
>> D, is there any way to do this?,
>> thanks for your help,
>> best
>> Jose
>> On 3 March 2017 at 21:25, Tarik S Bel-Bahar <tarikbelbahar at gmail.com>
>> wrote:
>>> Hello Jose,
>>> Yes you should be able to re-epoch, then run ICA on just the epochs
>>> without the buffer time,
>>> and then re-apply the ICA results to the files with the buffer time, and
>>> go from there.
>>> You may have to insert a new trigger, but you should be able to just
>>> "select an epoch start/end time that does include the buffer times. First
>>> try it with one file from the gui, and use eegh to build a script for that.
>>> Overall, if your buffer time is under ~2 seconds, and has no large
>>> artifacts, it would be okay to include them in the ICA. In other words,
>>> your ICA results should look very similar with either method (with or
>>> without the buffer periods).
>>> Check Makoto's general recommendations for ICA just in case, if you
>>> haven't had a chance to.
>>> On Fri, Mar 3, 2017 at 10:11 AM, José Luis <
>>> joseluisulloafulgeri at gmail.com> wrote:
>>>> hi,
>>>> I'm analysing EEG data and want to perform ERP and time-frequency
>>>> analyses,
>>>> I'm doing the pre-processing with EEGlab,
>>>> I wanted to move fast so I epoch my data and then I proceed with the
>>>> artefact rejection. I epoch my data taken into consideration that for
>>>> time-frequency I need a buffer zone,
>>>> Now, I want to perform ICA but only in a selected time period of
>>>> interest. I have several question here:
>>>> 1) Can I do ICA in select periods of time within my epochs?
>>>> 2) If not, I could try to re-epoch my dataset, perform ICA in the
>>>> re-epoched (shorter) dataset, and then re-inject the weight of the ICA back
>>>> to the original dataset), does that sound ok? I'm only interested in my
>>>> selected time period of interest, and the rest of the signal I would use it
>>>> because I need a buffer zone, and because long periods to compute power at
>>>> low frequencies,
>>>> 3) Can I epoch relative to two triggers, i.e. for a sequence of
>>>> triggers: A, B, C, D, E I want to do from -0.5 relative to A until E,
>>>> Thanks in advance for your help,
>>>> Jose
>>>> --
>>>> José Luis ULLOA FULGERI, PhD
>>>> +32477429007 <+32%20477%2042%2090%2007>
>>>> +32492646477
>>>> https://sites.google.com/site/joseluisulloafulgeri/
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>> --
>> +32477429007 <+32%20477%2042%2090%2007>
>> +32492646477
>> https://sites.google.com/site/joseluisulloafulgeri/

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