[Eeglablist] STUDY design: spectrum negative power values

[Christian Scharinger]

Dear eeglab users,

I use the following code for calculating the spectrum in a STUDY design:

[STUDY ALLEEG] = std_precomp(STUDY, ALLEEG, 'channels', 'design', [1], 
'erp', 'off', 'spec', 'on', 'ersp', 'off', 'specparams', { 'specmode', 
'psd', 'recompute', 'on', 'timerange', [1300 1800], 'freqfac', [4] }, 
'savetrials', 'off');

STUDY = pop_specparams(STUDY, 'groupstats','on', 'mcorrect','fdr', 
'threshold',0.05,'plotgroups','together','freqrange',[1 30], 
'rmsubjmean', 'off');

With this code, I'm getting negative power values when I use the 
std_specplot function for plotting (or when I do the plotting via GUI).

So I guess I'm not getting absolute power values (what I would like to 
have) but power values in relation to some kind of baseline.

Is it possible to get absolute power values for a spectrum in a STUDY 
design?
Where can I see/change what baseline eeglab uses for calculating power 
values?

Many thanks in advance,

Christian



-- 
Christian Scharinger, M.A.

Knowledge Media Research Center (KMRC)
Schleichstraße 6 | 72076 Tuebingen

Phone: +49 (0)7071 979-360
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