[Eeglablist] ERSP baseline question

[jekline at umich.edu]

Hello, I am creating ERSP plots using epoched EEG data and I had a
question. I collected data on subjects walking and performing a cognitive
task.

1. I epoched around each step with the left foot. I created component ERSP
plots through the GUI with the prestimulus baseline removed. I still see
activity (areas of higher or lower power from baseline) in the prestimulus
baseline. Is something going wrong? If I'm subtracting the baseline,
shouldn't there be no visible change in activity during the baseline time.
Thanks for any help.

Julia