[Eeglablist] Single trial data in newtimef()

[Arnaud Delorme]

Dear Sacha,


> 1.       newtimef() gives me the single trial data stored in “alltfdata”. The data are in complex format. Is there a way to get the data also in the same time-by-frequency power format as for the mean “ersp” output (log scale or absolute scale)?


Yes, to compute absolute power in single trials, do abs(alltfdata).^2 or alltfdata*conj(alltfdata) which is equivalent but faster.



> 2.       I define a prestimulus period for basline correction using the ‘trialbase’ option. Are the single trial data in “alltfdata” baseline corrected using this baseline specification? In the documentation to newtimef() it is written somewhere, that single trial baseline correction has to be done manually. Is the ‘trialbase’ option already sufficient or do I have to do it manually?


No, the single trials are not corrected in alltfdata. You will have to do it manually again. Note that single-trial baseline is not the standard default baseline. Do not use the log transformation (default) when you work with baseline corrected single trials or some values can blow off (because some values can be close to 0 and log(0) is minus infinite).


> 3.       Is there a difference between “alltfdata” and “alltfX”?


No, there is no difference.
Best regards,

A. Delorme


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