[Eeglablist] single trial ersp corrected for baseline

Pieranna Arrighi parrighi at dfb.unipi.it
Wed Jan 18 02:26:38 PST 2012


Dear all,

I need to obtain single trial power values of ersp computed in STUDY
corrected  by single trial baseline. As far as now I was unsuccesfull in
trying to reconstruct the steps between the .dattimef and the final
.datersp. This means that I have misinterpreted some of the steps required
to compute the mean ersp  from single trials.
Briefly, what I have been doing is:
X=.dattimef;
X=abs(X) to convert complex number into magnitude
X=X.^2 to obtain power values of single trials
X=mean(X) to obtain the mean among trials
X=10*log10(X) to log transform data
then I tryied vary obtions to normalize to the mean baseline (erspbase),
but, although the shape of the curve was very similar to that of the ERSP,
values did not match in amplitude, as I missed the right scale factor.

can somebody help me?
many thanks

Pieranna




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