[Eeglablist] About filter setting

Andreas Widmann widmann at uni-leipzig.de
Wed Nov 25 03:13:23 PST 2015

Hi Stella,

> 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.
No need to speculate. The BP is a very low frequency (<1 Hz) slow wave. I suggest having a look into the literature. You might want to start with:

Brunia, C.H.M., Boxtel, G.J.M. van, & Böcker, K.B.E. (2012). Negative slow waves as indices of anticipation: The Bereitschaftspotential, the Contingent Negative Variation, and the Stimulus-Preceding Negativity. In E.S. Kappenman & S.J. Luck (Eds.), The Oxford handbook of event-related potential components (pp. 189-207). Oxford: Oxford University Press.

In the appendix of the chapter clear recommendations for filter settings are given. For BP minimum recommended time constant is 5 s. Thus, high-pass cutoff frequency should not be higher than 0.03 Hz.

Hope this helps! Best,

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