LFP / EEG Blocks
Blocks for continuous signal processing: filtering, phase extraction, PSD, oscillation detection, and channel selection.
Bandpass Filter
bandpass_filter
Zero-phase Butterworth bandpass filter applied to a continuous signal.
Ports
| Port | Direction | Type | Description |
|---|---|---|---|
signal |
Input | NeuroData[raw_signal] |
Continuous signal to filter |
filtered |
Output | NeuroData[lfp] |
Bandpass-filtered signal |
Parameters
| Parameter | Type | Default | Description |
|---|---|---|---|
low_hz |
float | 4.0 |
Lower cutoff frequency (Hz) |
high_hz |
float | 12.0 |
Upper cutoff frequency (Hz) |
order |
int | 4 |
Filter order |
Extract Phase
extract_phase
Extracts instantaneous phase via the Hilbert transform. Output is phase in radians (−π to π).
Ports
| Port | Direction | Type | Description |
|---|---|---|---|
signal |
Input | NeuroData[lfp] |
Band-limited signal (e.g. theta-filtered LFP) |
phase |
Output | NeuroData[raw_signal] |
Instantaneous phase in radians (−π to π) |
Parameters
None.
Detect Theta Cycles
detect_theta_cycles
Detects individual theta cycle boundaries from an instantaneous-phase signal. Cycles are defined peak-to-peak (ascending zero-crossings of the Hilbert phase), so within each cycle the phase runs from 0° to 360° — the natural convention for phase precession analysis.
Ports
| Port | Direction | Type | Description |
|---|---|---|---|
phase |
Input | NeuroData[raw_signal] |
Instantaneous phase in radians from extract_phase |
theta_cycles |
Output | NeuroData[theta_cycles] |
(N_cycles × 2) array of [t_start, t_end] in seconds |
Parameters
| Parameter | Type | Default | Description |
|---|---|---|---|
min_cycle_dur |
float | 0.05 |
Minimum valid cycle duration in seconds |
max_cycle_dur |
float | 0.25 |
Maximum valid cycle duration in seconds |
channel_index |
int | 0 |
Which channel to use if phase is multi-channel |
Compute PSD
compute_psd
Computes power spectral density using Welch's method. Frequencies are stored in the timestamps field of the output.
Ports
| Port | Direction | Type | Description |
|---|---|---|---|
signal |
Input | NeuroData[raw_signal] |
Continuous signal |
psd |
Output | NeuroData[raw_signal] |
PSD array (power values); frequencies stored in timestamps |
Parameters
| Parameter | Type | Default | Description |
|---|---|---|---|
window_seconds |
float | 1.0 |
Welch window length in seconds |
overlap |
float | 0.5 |
Fractional overlap between windows (0–1) |
Detect Oscillation Epochs
detect_oscillation_epochs
Detects epochs where instantaneous power exceeds a z-score threshold above the mean envelope (e.g. theta bouts or ripples).
Ports
| Port | Direction | Type | Description |
|---|---|---|---|
signal |
Input | NeuroData[lfp] |
Band-limited signal |
epochs |
Output | NeuroData[raw_signal] |
N × 2 array of [start, stop] timestamps in seconds |
Parameters
| Parameter | Type | Default | Description |
|---|---|---|---|
threshold_sd |
float | 2.0 |
Threshold in standard deviations above mean envelope |
min_duration_sec |
float | 0.1 |
Minimum epoch duration in seconds |
Select LFP Channel
select_channel
Extracts one channel from a multi-channel NeuroData[lfp] and returns a 1-D NeuroData[lfp] suitable for downstream filtering and phase extraction.
Ports
| Port | Direction | Type | Description |
|---|---|---|---|
lfp |
Input | NeuroData[lfp] |
Multi-channel LFP (n_samples × n_channels) |
channel |
Output | NeuroData[lfp] |
Single-channel LFP (n_samples,) |
Parameters
| Parameter | Type | Default | Description |
|---|---|---|---|
channel_index |
int | 0 |
Zero-based index of the channel to extract |
Select Channel
select_reference_channel
Selects a single channel from a generic multi-channel NeuroData[raw_signal]. Use this when the signal has not yet been typed as LFP.
Ports
| Port | Direction | Type | Description |
|---|---|---|---|
signal |
Input | NeuroData[raw_signal] |
Multi-channel signal (N_samples × N_channels) |
channel |
Output | NeuroData[raw_signal] |
Single-channel signal (N_samples,) |
Parameters
| Parameter | Type | Default | Description |
|---|---|---|---|
channel_index |
int | 0 |
Zero-based index of the channel to extract |