Simply EEGLAB
High-pass & low-pass filtering
Station 3 · Lesson 2 · EEGLAB 2026.1
In the GUI
- ToolsFilter the dataBasic FIR filter (new, default)
- Lower edge of the frequency pass band (Hz)
0.1 - Higher edge of the frequency pass band (Hz)
- FIR Filter order (Mandatory even. Default is automatic*)
- Plot frequency responseOK
- Name it:
D1 hp0.1 - Overwrite it in memory (set=yes; unset=create a new dataset)OK
- FileSave current dataset as
D1_hp0.1.set - ToolsFilter the dataBasic FIR filter (new, default)
- Lower edge of the frequency pass band (Hz)
- Higher edge of the frequency pass band (Hz)
30 - OK
D1 hp0.1 lp30
Script
EEG = pop_eegfiltnew(EEG, 'locutoff', 0.1);
EEG.setname = 'D1 hp0.1';
EEG = eeg_checkset(EEG);
EEG = pop_saveset(EEG, 'filename', 'D1_hp0.1.set', 'filepath', pwd); % path copy: the next lesson starts here
EEG_lp = pop_eegfiltnew(EEG, 'hicutoff', 30); % exercise only: do not save
EEG_lp.setname = 'D1 hp0.1 lp30';Which value should I choose?
| Your goal | High-pass | Low-pass |
|---|---|---|
| ERP analysis | 0.1 Hz | 30 Hz |
| Computing ICA | 1 Hz, sometimes 2 | Usually not needed |
| Spectral analysis | 0.5 to 1 Hz | Not below the highest frequency you study |
Check
- Read what EEGLAB printed in the command window
- Compare the spectrum
- Look at the signal itself
For your Methods
Data were high-pass filtered using a zero-phase Hamming-windowed sinc FIR filter (passband edge 0.1 Hz, cutoff frequency [0.05] Hz at −6 dB, transition bandwidth [0.1] Hz, filter length [4225] points; pop_eegfiltnew, firfilt plugin 2.8, EEGLAB 2026.1; Widmann et al., 2015).