[Eeglablist] Numerical Values in STUDY Structure

Saim Rasheed saim_rasheed at hotmail.com
Thu Jul 1 08:18:47 PDT 2010


Thanks a lot, I got the trial by trial data from '*.dattimef' files. In '.ersp' files individual trials are not available, Are these values averaged across all the trial values?
In '.datitc' values are visible as complex numbers in Matlab workspace, I write the data into excell file, there it write only real part, not the complex part ?
I have to use the data (after conversion into another format) into LIBSVM for classification of my visual conditions. I dont know, How important is the complex part for ITC computations?

Saim 

> Date: Wed, 30 Jun 2010 11:34:10 -0700
> Subject: RE: [Eeglablist] Numerical Values in STUDY Structure
> From: julie at sccn.ucsd.edu
> To: saim_rasheed at hotmail.com
> CC: arno at ucsd.edu; eeglablist at sccn.ucsd.edu
> 
> There is an option in the precompute menu to save single-trial data, but you
> will have to recompute if you did not check this the first time around
> (default is NOT to save single trials because this occupies a remarkable
> amount of disk space). ITC, of course, is a value that is computed across
> trials.
> 
> Julie
> 
> -- 
> Julie Onton, PhD
> http://sccn.ucsd.edu/~julie
> 
> >
> >
> > Thankyou very much Julie and Arno,
> >
> > Your help really worked. I have got the ERSP and itc data into Matlab
> > workspace. I have got another problem.
> > I have recorded the data for three different visual stimuli conditions from 4
> > electrode positions at 256 samples per second. There are certain number of
> > time-locked trials, e.g. 60, 58 55 for three conditions respectively. Each
> > trial consists of 3 seconds of data containing 768 data points, which were
> > automatically processed into 200 time points and 100 frequency points from 3Hz
> > to 128Hz. Now I can see in workspace, 100*200 variable each for all electrode
> > positions as chan1_ersp, chan2_ersp, chan3_ersp and chan4_ersp. Trial
> > information is bit confused for me now. Is it lost now? Is it possible to
> > compute ERSP and ITC trial by trial because I need to process a single-trial
> > for each visual condition.
> > Thanks
> >
> > Saim
> >
> >
> >
> >> Subject: Re: [Eeglablist] Numerical Values in STUDY Structure
> >> From: arno at ucsd.edu
> >> Date: Tue, 29 Jun 2010 17:52:09 -0700
> >> To: saim_rasheed at hotmail.com; eeglablist at sccn.ucsd.edu
> >>
> >> Another simple solution is to add additional output to the STUDY plotting
> >> functions after copying them from the history.
> >> For instance, after creating or loading an EEGLAB STUDY, then precomputing
> >> the ERP for data channel, you may use the channel plotting interface to plot
> >> the ERP for electrode CZ (for instance). Then, the EEGLAB history contains
> >> the line
> >>
> >> STUDY = std_erpplot(STUDY, ALLEEG, 'channels', { 'cz' });
> >>
> >> Then, looking at the std_erpplot function help, you may add additional
> >> outputs
> >>
> >> [STUDY erp erptimes ] = std_erpplot(STUDY, ALLEEG, 'channels', { 'cz' });
> >>
> >> Note that the "erp" output will be a cell array containing an array for the
> >> ERP of each condition/group. If one subject only is present, each array will
> >> be a vector of values for the ERP of this subject in a given condition. If
> >> several subjects are present, each column of the array will contain the ERP
> >> for a given subject.
> >>
> >> Arno
> >>
> >> On Jun 29, 2010, at 10:46 AM, Julie Onton wrote:
> >>
> >> > Good question.
> >> >
> >> > Below is a script to help you find, load and plot your raw data.
> >> >
> >> > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> >> > % LOAD raw data:------------------------
> >> > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> >> > basedir = '/home/you/whereyourdatais/';
> >> >
> >> > subjs =
> >> > {'S01','S02','S03','S04','S05','S06','S07','S08','S09','S10','S11','S12','S13'};
> >> >
> >> > subj = 3; % who do you want to plot?
> >> > cond = 1; % what condition number?
> >> >
> >> > % for example, load ERSP:
> >> > load_string =
> >> > [basedir,subjs{subj},'\',STUDY.datasetinfo(1).filename(1:end-4),'.icaersp'];
> >> >
> >> > % OR ITC
> >> > load_string =
> >> > [basedir,subjs{subj},'\',STUDY.datasetinfo(1).filename(1:end-4),'.icaitc'];
> >> >
> >> > % OR spectra:
> >> > load_string =
> >> > [basedir,subjs{subj},'\',STUDY.datasetinfo(1).filename(1:end-4),'.icaspec'];
> >> >
> >> > % OR topomaps:
> >> > load_string =
> >> > [basedir,subjs{subj},'\',STUDY.datasetinfo(1).filename(1:end-4),'.icatopo'];
> >> >
> >> > % load the raw data into the variable 'RAWdata':
> >> > RAWdata = load('-mat',load_string);
> >> >
> >> > % Mask an ERSP using calculated bootstrap limits (if you calculated them):
> >> >
> >> > ic = 8; % choose IC to plot
> >> >
> >> > oneic = ['RAWdata.comp',int2str(ic),'_ersp'];
> >> > oneic = eval(oneic);
> >> > % in case you want to see the removed baseline:
> >> > onebase = ['RAWdata.comp',int2str(ic),'_erspbase'];
> >> > onebase = eval(onebase);
> >> > % load the bootstrap significance limits:
> >> > oneboot = ['RAWdata.comp',int2str(ic),'_erspboot'];
> >> > oneboot = eval(oneboot);
> >> >
> >> > maskERSP = oneic;
> >> > % zero out non-sig values:
> >> > maskERSP(find(oneic > repmat(oneboot(:,1),[1 size(oneic,2)])& oneic <
> >> > repmat(oneboot(:,2),[1 size(oneic,2)]))) = 0;
> >> >
> >> > clim = 4; % set +/- color limits
> >> > figure; imagesc(RAWdata.times,RAWdata.freqs,maskERSP,[-clim clim]);
> >> > set(gca,'ydir','norm');
> >> > title(['Subj ',int2str(subj),'; IC ',int2str(ic),';
> >> ',STUDY.condition{cond}]);
> >> > cbar;
> >> >
> >> >
> >> > Hope this helps, Julie
> >> >
> >> > --
> >> > Julie Onton, PhD
> >> > http://sccn.ucsd.edu/~julie
> >> >
> >> >>
> >> >>
> >> >>
> >> >> Hi,
> >> >>
> >> >>
> >> >>
> >> >> I am working with STUDY structure and computed ERSP, ITC and. I can plot
> >> them
> >> >> by a single click and analyse them.
> >> >>
> >> >> Where I can find the numerical values for ERSP and ITC ? Where these
> >> values
> >> >> are stored?
> >> >>
> >> >>
> >> >>
> >> >> I need them for further computations. Please help.
> >> >>
> >> >>
> >> >>
> >> >> Thanks.
> >> >>
> >> >>
> >> >>
> >> >> Saim
> >> >>
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