[Mne_analysis] events lost in epoching ?

[Jona]

I agree this is not intuitive, and at least would deserve an example (sorting by RT is an extremely natural thing for EEGLAB migrants ….).
I also find define_target_events <http://martinos.org/mne/stable/generated/mne.event.define_target_events.html#mne.event.define_target_events> not the most accessible function.

Boris, one thing I do is computing RTs on the raw file event arrays (usually, as Denis said, simply by calculating the difference between each event’s latency and the next event’s latency) and then storing that in the 2nd column of the events array. This is not the intended usage, but it will usually work (because the middle column is otherwise mostly useless).
MNE functions and methods preserve the middle column, and you can easily access it with e.g. epochs.events[:,1].


> Am 06.01.2016 um 14:28 schrieb mne_analysis-request at nmr.mgh.harvard.edu:
> 
> 
> 
> ------------------------------
> 
> Message: 5
> Date: Wed, 6 Jan 2016 14:28:38 +0100
> From: Boris BURLE <boris.burle at univ-amu.fr <mailto:boris.burle at univ-amu.fr>>
> Subject: Re: [Mne_analysis] events lost in epoching ?
> To: Discussion and support forum for the users of MNE Software
> 	<mne_analysis at nmr.mgh.harvard.edu <mailto:mne_analysis at nmr.mgh.harvard.edu>>
> Message-ID: <568D1686.4030107 at univ-amu.fr <mailto:568D1686.4030107 at univ-amu.fr>>
> Content-Type: text/plain; charset=windows-1252; format=flowed
> 
> On 06/01/2016 14:16, Denis A. Engemann wrote:
>> Note. You can compute all latencies solely based on the events array using the differences between the values in the first column, after transforming to time via sampling frequency.
>> Then there is 'epoch.selection' which gives you the indices of the epochs selected with respect to the original epochs. So you can easily map your eeg trials to external information. I am on my phone now, so I cannot give you a nice example unfortunately.
>> 
> 
> Sure, but that less convenient, and somehow more fragile: if I drop an 
> epoch, and forget to delete the corresponding RT in the list, there is 
> mismatch. This cannot append if I extract the RT directly from the epoch.
> 
> Beside computing RT, there are many other occasion where one needs to 
> sort trials based on the presence of other events in the epoch.
> 
> 	Thanks anyway for your help,
> 		B.
> 
> 
> 
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