[FieldTrip] Scaling issues with EEG time frequency analysis

[Arti Abhishek]

Thanks Peter. Perhaps I wasn't clear in the previous email. The time
frequency values that I got are too high. I had to changes the Z axis
limits to -500 to 500 instead of the [-3e-27 3e-27] values on the tutorial.
Is there anything I am doing wrong?
Thanks
Arti

On Mon, Oct 13, 2014 at 8:41 PM, Peter Goodin <pgoodin at swin.edu.au> wrote:

>  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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>
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