[Eeglablist] (no subject)

[kwhittin at fizz.phys.dal.ca]

  Hello again,

              I was wondering if someone could answer any (or all) of the
following 2 questions:

1) The output from Plot->Channel properties shows the power spectrum (as
computed using Matlabs' pwelch() function ).  The output is scaled in dB,
and (for my data anyway) is negative at some frequencies (indicating a
loss in power).  Just to be clear, is this because it uses some arbitrary
value for its baseline?  I just want to make sure its not using the
prestim interval.

2) The output from Plot > Time frequency transforms > Channel
time-frequency shows another form of the power spectrum.  Again, just to
be clear, does this one show the changes in post-stimulus power relative
to the mean pre-stim interval?

Thanks,
Kevin



--
Kevin Whittingstall, Ph.D.
Dept. of Physics
Dalhousie University
Halifax, NS, Canada