[FieldTrip] No trialinfo after epoching

[Schoffelen, J.M. (Jan Mathijs)]

Hi Arti,

I think that this can be easily fixed. Notably, if you have a look at ft_trialfun_general, there’s a specific string-to-number conversion for eventtypes that start with ’S’, or ‘R’. This happens on line 210/211. It might be possible to come up with a generic solution, but this will result in a more or less arbitrary string-to-number mapping. The ’S’ and ‘R’ eventvalues pertain to a particular acquisition system that codes stimuli and responses as ‘Sx’, and ‘Rx’ respectively, where the ‘x’ is a user-specified value.
If you come up with a sensible generic solution I’d be more than happy to build it into the code, or you can do so yourself, and submit this to our github repository as a pull request.

Best wishes,
Jan-Mathijs

On 28 Jun 2016, at 04:01, Arti Abhishek <mailtome.2113 at gmail.com<mailto:mailtome.2113 at gmail.com>> wrote:

Dear list,

I am following up on my previous question on mussing trial info after I epoch the data. The fourth column in the data.cfg.trial is present when the triggers are neumeric. But when the triggers are in string format (as in EGI system eg. "DIN8"), the fourth column is not present with the following code. I would really appreciate if someone could suggest a fix.

cfg                     = [];
cfg.dataset             = 'LL1101_20160622_022943.raw';
cfg.trialdef.prestim    = 0.1;
cfg.trialdef.poststim   = 0.5;
cfg.trialdef.eventtype   = 'trigger';
cfg.trialdef.eventvalue  = {'DI14', 'DI16', 'DI18', 'DI22', 'DI24', 'DIN4','DIN6', 'DIN8'};
data               = ft_definetrial(cfg);
LL01_epochs             = ft_redefinetrial(data, LL01_cont);

Thanks,
Arti

On Mon, Jun 27, 2016 at 5:18 PM, Arti Abhishek <mailtome.2113 at gmail.com<mailto:mailtome.2113 at gmail.com>> wrote:
Dear list,

I am trying to analyse EEG data recorded in EGI system. When I used the following code to epochs the data, the trialinfo information is missing that prevents me to average each trigger seperately. Could anyone suggest a fix?

cfg                     = [];
cfg.dataset             = 'LL1101_20160622_022943.raw';
cfg.trialdef.prestim    = 0.1;
cfg.trialdef.poststim   = 0.5;
cfg.trialdef.eventtype   = 'trigger';
cfg.trialdef.eventvalue  = {'DI14', 'DI16', 'DI18', 'DI22', 'DI24', 'DIN4','DIN6', 'DIN8'};
data               = ft_definetrial(cfg);
LL01_epochs             = ft_redefinetrial(data, LL01_cont);

Thanks,
Arti


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