FieldTrip

Definetrial and preprocessing require the original MEG dataset, which is available from ftp://ftp.fcdonders.nl/pub/fieldtrip/tutorial/Subject01.zip.

% find the interesting segments of data
cfg = [];                                                  % empty configuration
cfg.dataset                 = 'Subject01.ds';              % name of CTF dataset  
cfg.trialdef.eventtype      = 'backpanel trigger';
cfg.trialdef.prestim        = 1;
cfg.trialdef.poststim       = 2;
cfg.trialdef.eventvalue     = 3;                     
cfg = definetrial(cfg);            

% preprocess the data
cfg.trl([15, 36, 39, 42, 43, 49, 50, 81, 82, 84],:) = [];  % remove the segments that have artifacts
cfg.channel  = {'MEG', '-MLP31', '-MLO12'};                 % read all MEG channels except MLP31 and MLO12
cfg.detrend  = 'yes';   
dataFIC2freq = preprocessing(cfg);                      

These data have been cleaned from artifacts by removing several trials and two sensors; see visual_artifact_rejection. For time-frequency analysis of power it is recommended to 'detrend' each trial (removes the DC offset and linear trend).

Subsequently you can save the data to disk.

save dataFIC2freq dataFIC2freq