[FieldTrip] mytrialfun & ft_read_event

[Harsimrat Singh]

Hi All****

** **

I am trying to read in my data in which the first channel contains the
marker signal (spike) superimposed on the trigger channel.****

I would like to use mytrialfun before ft_definetrial. To do this I would
like to check the value of the marker channel and compare it with mean
value of the channel and record that value in the even field.****

But I guess I can’t do it as the fieldtrip doesn’t read the channel values
before ft_definetrial.  Can I use data channel values in mytrialfun? If
not, is there a way around this?****

** **

Here is my trialfun****

** **

function [trl, event] = mytrialfun(cfg)****

** **

% read the header information and the events from the data****

hdr   = ft_read_header(cfg.datafile);****

event = ft_read_event(cfg.datafile,'trigindx',1,'threshold',5e2,
'detectflank','up');****

** **

% search for "trigger" events according to 'trigchannel' defined outside
the function

The problem lies here

**

*value = [event(find(cfg.trialdef.trigchannel (it needs data of this
channel & not channel
name))>mean(cfg.trialdef.trigchannel)+500)]*%mkrchannel is
data.trial{1}(1,:));

** **

% creating your own trialdefinition based upon the events****

for j = 1:length(value);****

    trlbegin = sample(j) + pretrig;****

    trlend   = sample(j) + posttrig;****

    offset   = pretrig;****

    newtrl   = [ trlbegin trlend offset];****

    trl      = [ trl; newtrl];  ****

end****

** **

** **

Thanks in advance****

Best regards****

Harsimrat****
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