[Eeglablist] Fwd: About filter setting

Makoto Miyakoshi mmiyakoshi at ucsd.edu
Tue Dec 1 11:47:57 PST 2015

Dear Fang-Yu,

You save .set, 1-Hz high-pass, run ICA, apply the ICA weight matrix to the
.set to obtain un-highpassfiltered results. This is an old trick once
recommended by Stefan Debener in SCCN. Then you may want to apply high-pass
with very low cut-off. Follow Andreas's recommendation:

> Thus, high-pass cutoff frequency should not be higher than 0.03 Hz.


On Mon, Nov 23, 2015 at 11:44 PM, Fang-Yu Chang <hardheard101 at gmail.com>

> Dear eeglablists
> I would like to analyze the bereitschaftpotential (BP), and I have 2
> questions which are related to set the filter's condition.
> First, I set high-pass filter at 1 Hz and low-pass filter at 30 Hz. After
> running ica, there  was 30 Hz amplitude in every independent component
> (IC). However, high-pass filter at 1 Hz and low-pass at 70 Hz were set, and
> there was no amplitude in every IC. I would like to ask how did it happen?
> Second, I noticed that there is a difference between setting high-pass
> filter at 0.1 Hz and setting high-pass filter at 1 Hz. If high-pass was set
> at 0.1 Hz, the amplitude of the peak was about 27 microVolts, but if
> high-pass filter was set at 1 Hz, the amplitude of the peak was about 5
> microVolts. My vice mentor speculates that BP is a kind of slow wave, so
> it's reasonable that we set high-pass filter at 0.1Hz. Nevertheless, we
> would like to ask experts' opinions. According to previous studies, the
> amplitude of BP is about 10 microVolts in the healthy adults.
> The pictures for low-pass filters were set at 70 Hz and 30 Hz separately.
> Low-pass filter at 70 Hz
> http://imgur.com/L5tAxx6
> Low-pass filter at 30 Hz
>  http://imgur.com/5SwNDZv
> In addition, here is my system information: Matlab is 2014a and eeglab is
> 13.5.4b.
> Thank you.
> Sincerely,
> Stella Ling
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Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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