Do I need ECG channel to run "artifact_ecg"

[Jim Li]

Dear Andrej,

Thanks a lot for your feedback. I tried your recommendation 
of "cfg.artfctdef.ecg.channel  = {'A229'};" but I got the same message. 

In fact, last night by a little debugging I figured out why the error message 
occured. And the solution is to simply add this line before doing artifact_ecg:
cfg.artfctdef.ecg.inspect   = {'A229'}; 

And that worked beautifully. 

cheers,

Jim

On Thu, 23 Apr 2009 09:01:15 +0100, Stancak, Andrej 
<A.Stancak at LIVERPOOL.AC.UK> wrote:

>Dear Jim-Li,
>
>  I probably faced the same error message when I was writing my script for 
ECG artefact removal. I remember to get rid of this error message by putting 
the ECG channel label into brackets:
>
> cfg.artfctdef.ecg.channel  = {'A229'};
>
> 
> I hope I have not mislead you as I am a FieldTrip novice, but it is maybe 
worth trying. 
>
>Best wishes
>Andrej  
>
>
>
>Andrej Stancak, PhD.
>Professor for normal physiology
>Senior lecturer in psychology
>
>School of Psychology
>Eleanor Rathbone Building
>Bedford Street South
>L69 7ZA
>Liverpool
>United Kingdom
>
>Phone: 0044 0151 7946951
>E-mail: a.stancak at liverpool.ac.uk (primary)
>        stancak at lf3.cuni.cz (secondary)
>
>Office hours: Mo 10-12, Wed 10-12
>
>
>-----Original Message-----
>From: FieldTrip discussion list [mailto:FIELDTRIP at NIC.SURFNET.NL] On Behalf 
Of Jim Li
>Sent: 22 April 2009 17:23
>To: FIELDTRIP at NIC.SURFNET.NL
>Subject: [FIELDTRIP] Do I need ECG channel to run "artifact_ecg"
>
>Dear all,
>
>
>W/ a 041809 Fieldtrip, I tried to run the following lines but got some error 
(see 
>below). I don't have ECG channel in my data, that's why I use a left-most 
>MEG channel w/ apparent cardiac interferences instead. Any suggestion how 
>to fix the problem?
>
>-------------
>cfg                      = [];
>cfg.trl                  = data.cfg.previous.trl;
>cfg.dataset              = data.cfg.previous.dataset;
>cfg.continuous            = 'yes' ;
>cfg.artfctdef.ecg.channel  = 'A229'; 
>cfg.artfctdef.ecg.pretim = 0.25;
>cfg.artfctdef.ecg.psttim = 0.5; 
>cfg.artfctdef.ecg.method  = 'zvalue'; %peak-detection method
>cfg.artfctdef.ecg.cutoff  = 3; %peak-threshold
>[cfg, artifact]          = artifact_ecg(cfg);
>
>current  zvalue threshold = 3.000
>keep the current value (y/n) ?
>y
>??? Undefined function or variable "labelmlt".
>
>Error in ==> channelselection at 344
>if findmlt,        channel = [channel; labelmlt]; end
>
>Error in ==> artifact_ecg at 238
>sgn    = channelselection(artfctdef.inspect, hdr.label);
>
>----------------------------------
>The aim of this list is to facilitate the discussion between users of the 
FieldTrip  toolbox, to share experiences and to discuss new ideas for MEG and 
EEG analysis. See also http://listserv.surfnet.nl/archives/fieldtrip.html and 
http://www.ru.nl/neuroimaging/fieldtrip.
>
>----------------------------------
>The aim of this list is to facilitate the discussion between users of the 
FieldTrip  toolbox, to share experiences and to discuss new ideas for MEG and 
EEG analysis. See also http://listserv.surfnet.nl/archives/fieldtrip.html and 
http://www.ru.nl/neuroimaging/fieldtrip.

----------------------------------
The aim of this list is to facilitate the discussion between users of the FieldTrip  toolbox, to share experiences and to discuss new ideas for MEG and EEG analysis. See also http://listserv.surfnet.nl/archives/fieldtrip.html and http://www.ru.nl/neuroimaging/fieldtrip.