[FieldTrip] Where to add a trialfun?

[Lam, Nietzsche]

Hi Ana Laura,

In general, you need to determine which trial function (Trialfun) to use when using definetrial (see this tutorial: http://fieldtrip.fcdonders.nl/tutorial/preprocessing  under "do the trial definition for the fully incongruent (FIC) condition).

Please try adding this: "cfg.trialfun = 'trialfun_bit2dec(cfg)". to your code before calling definetrial (see below).

  % TRIAL DEFINITION
    cfg=[];
    cfg.filename = ['my/folders/', subject, '.RAW']; 
    cfg.headerfile = ['my/folders/', subject, '.RAW']; 

    cfg.trialdef.eventtype    = 'STATUS';
    cfg.trialdef.eventvalue   = cgrmrk; 
    cfg.trialdef.prestim      = 0.2; 
    cfg.trialdef.poststim     = 1;   
    cfg.trialdef.eventtype=?;
    cfg.trialfun              = 'trialfun_bit2dec(cfg)  %% trialfun definition
    cfg = definetrial(cfg);


As an addition note: based on your error message, it seemed that the problem was in the function trialfun_bit2dec. However, from the code you showed us, you haven't referenced/called this function. I was wondering if the code you provide corresponded to the code that created your error message?  I'm guessing you ran [trl] =trialfun_bit2dec(cfg) directly (i.e. not via definetrial). In which case, it was looking for cfg.trialdef.eventtype.  You can call trialfun_bit2dec as long as you have all the relevant information in the cfg (which is in the code you showed us).  Hope this helps.

Best,
Nietzsche
 



----- Original Message -----
> From: "Ana Laura Diez Martini" <diezmartini at gmail.com>
> To: "FieldTrip discussion list" <fieldtrip at science.ru.nl>
> Sent: Saturday, 27 September, 2014 2:42:21 AM
> Subject: [FieldTrip] Where to add a trialfun?
> Hello all! I'm having a simple problem. I want to add this trialfun:
> 
> http://fieldtrip.fcdonders.nl/faq/how_can_i_transform_trigger_values_from_bits_to_decimal_representation_with_a_trialfun
> 
> 
> 
> I get this error:
> 
> 
> 
> Reference to non-existent field 'trialdef'.
> 
> 
> Error in trialfun_bit2dec (line 52)
> if strcmp(event(i).type, cfg.trialdef.eventtype)
> 
> 
> I'm quite sure it's because I'm not writing it in the correct part of
> my script. This is my trial definition part. Where should I add it and
> how should I write the line?
> 
> 
> 
> % TRIAL DEFINITION
> cfg=[];
> cfg.filename = ['my/folders/', subject, '.RAW'];
> cfg.headerfile = ['my/folders/', subject, '.RAW'];
> 
> 
> cfg.trialdef.eventtype = 'STATUS';
> cfg.trialdef.eventvalue = cgrmrk;
> cfg.trialdef.prestim = 0.2;
> cfg.trialdef.poststim = 1;
> cfg.trialdef.eventtype=?;
> 
> 
> cfg = definetrial(cfg);
> 
> 
> trl = cfg.trl;
> cfg=[];
> cfg.dataset = ['my/folders/', subject, '.RAW'];
> cfg.trl = trl;
> cfg.reref = 'yes';
> cfg.refchannel = ['all'];
> 
> 
> THANKS!
> _______________________________________________
> fieldtrip mailing list
> fieldtrip at donders.ru.nl
> http://mailman.science.ru.nl/mailman/listinfo/fieldtrip

-- 
Nietzsche H.L. Lam, MSc 
PhD Candidate 

Max Planck Institute for Psycholinguistics 
Wundtlaan 1, 6525 XD Nijmegen, The Netherlands 

Donders Institute for Brain, Cognition and Behaviour, 
Centre for Cognitive Neuroimaging, 
Kapittelweg 29, 6525EN Nijmegen, The Netherlands 

n.lam at fcdonders.ru.nl 
+31-24-3668219 


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