[Eeglablist] extracting non event related epochs

[James Desjardins]

Hi Payashi,

To select epochs I would use pop_select in the form:

EEG=pop_select(EEG,'trial',[900:960]);

... where the values [900:960] refer to trial/epoch indices.

If you used the vised_marks plugin to generate the regular interval epochs there should be a field in the EEG.epoch structure named "startpnt" that represents the data point index from the continuous data where the current epoch originated. So if you wanted to extract all of the epochs that originated between 5 minutes and 6 minutes (between 300 and 360 seconds) in the continuous data you could use the following:

epoch_inds=find([EEG.epoch.startpnt]>300*EEG.srate & [EEG.epoch.startpnt]<360*EEG.srate);
EEG=pop_select(EEG,'trial',epoch_inds);


Let me know if this is what you need.

James Desjardins, MA
Electrophysiology Technologist
Cognitive and Affective Neuroscience Lab, Psychology Department
Jack and Nora Walker Centre for Lifespan Development Research
Brock University
500 Glenridge Ave.
St. Catharines, ON, Canada L2S 3A1
905-688-5550 x4676
--
"'Cause you never can tell What goes on down below!
"This pool might be bigger Than you or I know!"

McElligot's Pool
Dr.Seuss 1947

________________________________________
From: eeglablist-bounces at sccn.ucsd.edu [eeglablist-bounces at sccn.ucsd.edu] on behalf of Payashi Garry [payashi.garry at ndcn.ox.ac.uk]
Sent: August-18-14 4:46 AM
To: eeglablist at sccn.ucsd.edu
Subject: [Eeglablist] extracting non event related epochs

Dear EEG lab list,

I have resting EEG data recordings which are 2 hours in length. I wish to extract 30 one second epochs from various portions of the data. I have epoched the data using the vised marks plugin, but I am struggling to extract the desired epochs as there are no 'events' as such to mark the data.

Do you have any advice on how to go about doing this?

Many thanks
Best wishes
Payashi

****
Dr Payashi Garry MB BChir FRCA
Specialty Registrar in Anaesthetics and BRC Research Fellow
Nuffield Department of Clinical Neurosciences
John Radcliffe Hospital
Oxford OX3 9DU
Tel: 01865 572878


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