[FieldTrip] concatenating data to a single trial data set

[Andreas Wollbrink]

Dear Eelke, dear Nathan,

thanks for your help on a way to concatenate the data.

In the end I successfully used a mixture of both approaches you suggested.

Best,
Andreas

On 06/20/11 15:35, Eelke Spaak wrote:
> Dear Andreas,
>
> The way I concatenate data is just 'manually', so without the
> intervention of FieldTrip. To do this, you will have to concatenate
> the arrays in both the data.trial and the data.time cell array.
>
> In pseudocode:
>
> initialize matrix data_concat of size channels X total time points
> initialize matrix time_concat of size 1 X total time points
>
> loop over data.trial and data.time (have the same size)
>    data_concat(:,appropriate time indices) = data.trial{k}(:,:);
>    time_concat(1,appropriate time indices) = data.time{k}(:);
> end loop
>
> data.trial = data_concat;
> data.time = time_concat;
>
> That should do the trick. I would have provided actual code, were it
> not that I am doing something slightly different from what you are
> asking.
>
> I hope this helps!
>
> Best,
> Eelke
>
> 2011/6/20 Andreas Wollbrink<a.wollbrink at uni-muenster.de>:
>> Dear all,
>>
>> in order not to run into a RAM memory overload when performing an ICA on MEG
>> data I subdivided the raw data into several equally long segments (chops)
>> using ft_preprocessing with varying cfg.trl settings.
>> After applying ft_componentanalysis to each of these chops I removed some
>> (bad) components and backprojected the data to seperate data matrices using
>> the following code:
>>
>> cfg = [];
>> cfg.component = badCompVec; % to be removed component(s)
>> dataCorr = ft_rejectcomponent(cfg, compData);
>>
>>
>> Finally I like to concatenate these data to a continuous (single trial) data
>> matrix in order to compare it with the original raw data set and perform the
>> further timelock analysis on it.
>>
>> I tried using ft_appenddata for this issue. Doing so one gets a multi trial
>> data matrix which I could not convert to single trial continuous data matrix
>> using e.g. ft_redefinetrial.
>>
>> I would appreciate any help in how to solve this problem.
>>
>> Thanks in advance.
>>
>> Andreas Wollbrink
>> --
>>
>>
>> ======================================================================
>>
>>   Andreas Wollbrink, Biomedical Engineer
>>
>>   Institute for Biomagnetism and Biosignalanalysis
>>   Muenster University Hospital
>>
>>   Malmedyweg 15         phone:   +49-(0)251-83-52546
>>   D-48149 Muenster      mobil:   +49-(0)160-98527553
>>   Germany               fax:     +49-(0)251-83-56874
>>                         e-Mail: a.wollbrink at uni-muenster.de
>>
>> ======================================================================
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>
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-- 


======================================================================

   Andreas Wollbrink, Biomedical Engineer

   Institute for Biomagnetism and Biosignalanalysis       	
   Muenster University Hospital

   Malmedyweg 15         phone:   +49-(0)251-83-52546
   D-48149 Muenster      mobil:   +49-(0)160-98527553
   Germany               fax:     +49-(0)251-83-56874	
                         e-Mail: a.wollbrink at uni-muenster.de

======================================================================