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iCAPs/packages/spm12/man/example_scripts/spm_eeg_convert_arbitrary_data.m
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spm_eeg_convert_arbitrary_data.m
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% demo for creating an SPM M/EEG dataset from arbitrary data using
% conversion of simple Fieldtrip raw data struct.
% SPM8 internal format is quite complex but is transparent to the user
% as meeg object's methods take care of maintaining its consistency.
% The most straightforward way to convert arbitrary data that is available
% as an ASCII file or *.mat file with some variables to SPM8 is to create
% a quite simple Fieldtrip raw data struct and then use SPM's
% spm_eeg_ft2spm to convert this struct to SPM8 file. Missing information
% can then be supplemented using meeg methods and SPM functions.
% Fieldtrip raw struct must contain the following fields:
% .fsample - sampling rate (Hz)
% .trial - cell array of matrices with identical dimensions channels x time
% .time - cell array of time vectors (in sec), the same length as the
% second dimension of the data. For SPM8 they must be identical.
% .label - cell array of strings, list of channel labels. Same length as
% the first dimension of the data.
%__________________________________________________________________________
% Copyright (C) 2010 Wellcome Trust Centre for Neuroimaging
% Vladimir Litvak
% $Id: spm_eeg_convert_arbitrary_data.m 5404 2013-04-12 15:08:57Z vladimir $
% Initialize SPM
%--------------------------------------------------------------------------
spm('defaults','EEG');
% Some details about the data
%--------------------------------------------------------------------------
Nchannels = 5;
Nsamples = 500;
Ntrials = 50;
TimeOnset = -0.1; % in sec
Fsample = 1000;
chlabels = {
'LFP1'
'LFP2'
'LFP3'
'LFP4'
'LFP5'
};
% define the output file name
%--------------------------------------------------------------------------
fname = 'arbitrary_data_example';
% create data array
%--------------------------------------------------------------------------
data = randn([Nchannels, Nsamples, Ntrials]);
% create the time axis (should be the same for all trials)
%--------------------------------------------------------------------------
timeaxis = [0:(Nsamples-1)]./Fsample + TimeOnset;
% Create the Fieldtrip raw struct
%--------------------------------------------------------------------------
ftdata = [];
for i = 1:Ntrials
ftdata.trial{i} = squeeze(data(:, :, i));
ftdata.time{i} = timeaxis;
end
ftdata.fsample = Fsample;
ftdata.label = chlabels;
ftdata.label = ftdata.label(:);
% Convert the ftdata struct to SPM M\EEG dataset
%--------------------------------------------------------------------------
D = spm_eeg_ft2spm(ftdata, fname);
% Examples of providing additional information in a script
% [] comes instead of an index vector and means that the command
% applies to all channels/all trials.
%--------------------------------------------------------------------------
D = type(D, 'single'); % Sets the dataset type
D = chantype(D, ':', 'LFP'); % Sets the channel type
D = conditions(D, 1:Ntrials, 'Condition 1'); % Sets the condition label
% save
%--------------------------------------------------------------------------
save(D);
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