[FieldTrip] Scaling issues with EEG time frequency analysis
Peter Goodin
pgoodin at swin.edu.au
Mon Oct 13 11:41:20 CEST 2014
Hi Arti,
Try lowering the cfg.zlim values (%% Plot TFR).
Peter
__________________________
Peter Goodin,
BSc (Hons), Ph.D Candidate.
Brain and Psychological Sciences Research Centre (BPsych)
Swinburne University,
Hawthorn, Vic, 3122
http://www.swinburne.edu.au/swinburneresearchers/index.php?fuseaction=profile&pid=4149
Monash Alfred Psychiatry Research Centre (MAPrc)
Level 4, 607 St Kilda Road,
Melbourne 3004
________________________________
From: fieldtrip-bounces at science.ru.nl [fieldtrip-bounces at science.ru.nl] on behalf of Arti Abhishek [mailtome.2113 at gmail.com]
Sent: Monday, 13 October 2014 5:49 PM
To: fieldtrip at science.ru.nl
Subject: [FieldTrip] Scaling issues with EEG time frequency analysis
Dear fieldtrip users,
I am a new fieldtrip user and I am having some problems with frequency analysis. My EEG data is recorded from Neuroscan NuAmps system (22 bit). I have used the following script (I wrote the script from the examples on the fieldtrip website), but I get the time frequency plots with huge values. Could anyone please suggest me what I am doing wrong?
Thanks
Arti
cfg =[];
cfg.dataset = 's01.cnt';
cfg.channel = {'all'};
cfg.layout = 'NuAmps.lay';
lay = ft_prepare_layout(cfg);
% Event identification
cfg.trialdef.eventtype = 'trigger';
cfg.trialdef.eventvalue = 101;
cfg.trialdef.prestim = 1;
cfg.trialdef.poststim = 2;
cfg.reref = 'yes';
cfg.implicitref = 'A1';
cfg.refchannel = {'A1' 'A2'};
cfg = ft_definetrial(cfg);
% % Filtering
% cfg.hpfilter = 'yes';
% cfg.hpfreq = 0.1;
% cfg.hpfilttype = 'fir';
dataFIC = ft_preprocessing(cfg);
%% Summary detection of bad trials
cfg = [];
cfg.method = 'summary';
cfg.layout = lay; % this allows for plotting
cfg.channels = [1:34];
data_clean = ft_rejectvisual(cfg, dataFIC);
% Calculate TFR for condition1
cfg = [];
cfg.trials = find(data_clean.trialinfo==101);
cfg.channel = 'EEG';
cfg.method = 'wavelet';
cfg.width = 7;
cfg.output = 'pow';
cfg.foi = 2:2:48;
cfg.toi = -0.5:0.05:1;
s01_TFRwave4ch = ft_freqanalysis(cfg, data_clean);
%% Plot TFR
cfg = [];
cfg.baseline = [-0.5 -0.1];
cfg.baselinetype = 'absolute';
cfg.zlim = [-500 500];
cfg.showlabels = 'yes';
cfg.layout = lay;
figure
ft_multiplotTFR(cfg, s01_TFRwave4ch)
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