[Eeglablist] Baseline in block design

[patrick bedard]

Hi everyone

I'm quite new at EEG analysis.
I have a block design 30 sec ON, 30 sec OFF, starting with ON, in 2 groups
(controls, patients).
It's a fatigue paradigm so performance changes rapidly from block to block
(within blocks too, but that's for another day!!).
I want to compare between groups for each block using time-frequency I
computed with discrete FFT at each second (30 datapoints per block).

My question is about the baseline. I don't think I have one since the exp
started with the ON condition. And it seems it's important to remove the
baseline in EEG analysis.
Is it in my contextI
Do I need to compute and remove a baseline from the ON blocks to be able to
interpret them correctly?
Can't I just compare the 2 groups directly at each block?

thanks in advance for your time
pat

------------------------------------
Patrick Bédard
Researcher
National Institutes of Health
401-270-5361