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[Preprint]. 2023 Dec 12:2023.05.25.542359. Originally published 2023 May 26. [Version 2] doi: 10.1101/2023.05.25.542359

Figure 1.

Figure 1.

Frequency response functions for several filters and their application to a single-participant ERP waveform and to a simulated N170 waveform. The frequency response functions quantify the extent to which a given frequency is passed versus blocked by the filter. (a) Frequency response functions for low-pass filters. Two cutoff frequencies are shown (5 Hz and 20 Hz), combined with four roll-off slopes (12 dB/octave, 24 dB/octave, 36 dB/octave, and 48 dB/octave). (b) Frequency response functions for high-pass filters. Two cutoff frequencies are shown (0.1 Hz and 0.5 Hz), combined with four roll-off slopes (12 dB/octave, 24 dB/octave, 36 dB/octave, and 48 dB/octave). (c) Averaged ERP waveform with different half-amplitude low-pass filter cutoffs (no filter, 5 Hz, 10 Hz, and 20 Hz, all with slopes of 12 dB/octave). (d) The same averaged ERP waveform with different half-amplitude high-pass filter cutoffs (no filter, 0.1 Hz, 0.5 Hz, and 2 Hz, all with slopes of 12 dB/octave). (e) and (f) Simulated N170 waveform filtered by a 5Hz low-pass filter and 2Hz high-pass filter (12 dB/octave). Note that the filters used for (c) and (d) were applied to the continuous EEG data prior to epoching and averaging. All filters used here were noncausal Butterworth filters, and cutoff frequencies indicate the half-amplitude point. The waveforms in (c) and (d) were from the face condition in the ERP CORE N170 paradigm, Subject 40, CPz electrode site.