[FieldTrip] Header file for TDT system

[Eelke Spaak]

Dear Shilpa,

If you already have the data and related information in Matlab, it is
probably best to skip the entire trial-definition step when converting
your data to FieldTrip format. It's quite straightforward to convert
data into a format that FT can handle, especially if you just want it
to have a single segment (or 'trial'). In your case, from the top of
my head, you could initialize a structure with the following fields:

data.label = abfi.recChNames;
data.trial = {yourDataMatrix}; % assuming size(yourDataMatrix) ==
[nChans nSamples]
data.fsample = 1000;
data.time = {0:1/data.fsample:lastTimePoint};
data.sampleinfo = [1 nSamples];

This is just about the bare minimum that FT requires, which in your
case should be sufficient. Note that both the data.trial and data.time
fields should be cell arrays, with one element per trial in your data.

For more detailed information about how FT raw data should look, see
the following entry on our wiki:
http://fieldtrip.fcdonders.nl/faq/how_are_the_various_data_structures_defined
.

Hope this was of help,
Best,

Eelke

2011/8/15 shree b <shreesb at yahoo.com>:
> Hello,
> I am new to field-trip and wanted to use your analysis on 16 channel continous LFP recordings from the TDT (Tucker Davis Technology) system. As there isn't a provision to read TDT header files I tried to input the values directly into the structure array.
>
> 1)I have already imported my data into Matlab and have the information that is need to be included in cfg.headerfile in a structure array:
>
> hdr=[];
>
> hdr.Fs=1000;
> hdr.nChans=16;
> hdr.nSamples= abfi.dataPtsPerChan; %abfi.dataPtsPerChan=620646
> hdr.nSamplesPre=0;
> hdr.nTrials=1;
> hdr.label= abfi.recChNames;
> %abfi.recChNames is a cell array with the channel names:    %IN0,IN1,IN2,IN3,IN4,IN5,IN6,IN7,IN8,IN9,IN10,IN11,IN12,IN13,IN14,IN15
>
> 2) The data is in a mat file with all 16 channels labeled as before
>
> 3) I defined trl as:
> a=1;
> b=length(IN0);
> c=0;
>
> trl=[a b c];% single trial no offset
>
> cfg=struct('headerfile',hdr,'datafile', data,'trl',trl)
>
> This approach isn't working, could you please tell me how I should specify the values for the header file and data structure.
>
> thanks very much
> Shilpa
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