[Eeglablist] Power reduction issue after rejecting ICs

[Makoto Miyakoshi]

Deara Maryam,

> I calculated the power reduction changes(after rejection vs.before ), and
it's around 46%!

Good point! I like it. I appreciate you computed it for confirmation.
Yes, actually that sounds right to me.
Did you think the brain in the skull is louder than the muscles surrounding
it?

If you think 46% is too big, *why* do you think so? On what criteria?

In fMRI, the BOLD signal is derived from only a few percent changes in MR
images. Which means people discard 98% of the raw signals (in a sense).
Does it undermine fMRI studies?

EEG is actually known for the high signal to noise ratio.

Makoto

On Fri, Mar 13, 2015 at 2:39 PM, Rohafza, Maryam <mr226 at njit.edu> wrote:

> Hello,
> I use ICA to reject eye blink, muscle artifact,etc...
> I calculated the power reduction changes(after rejection vs.before ), and
> it's around 46%!
> after preprocessing I'll be doing fft and subsequent power analysis. Is it
> OK to proceed since power reduction is around 50%?
> Is there any alternative way of rejecting artifacts,... so I don't have
> that much of power reduction?
> Thanks in advance for any advice
>
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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