Author: Alicia Garrido-Peña
Institution: Grupo de Neurocomputación Biológica, Universidad Autónoma de Madrid
License: GNU General Public License v3.0
RTXI Version: 2.0+
Status: Stable
WaveformAnalyzer is an RTXI plugin designed for real-time analysis of intracellular neuronal signals. This module detects action potentials ("spikes") and computes key metrics such as duration, amplitude, and depolarization/repolarization slopes. It also includes optional signal filtering and detailed analysis within a configurable time window around each spike.
This plugin is ideal for online waveform characterization, spike detection, and event-triggered data processing in electrophysiological experiments.
- Real-time detection of action potentials from voltage traces.
- Extracts waveform characteristics:
- Duration (ms)
- Amplitude (V)
- Depolarization slope
- Repolarization slope
- Min/Max voltages
- Optional signal filtering using a simple weighted moving average.
- Configurable threshold for spike detection.
- Adjustable time window and slope calculation window.
| Name | Description |
|---|---|
| Living neuron | Voltage signal to analyze (in Volts). |
| Name | Description | Type |
|---|---|---|
| Firing threshold (V) | Voltage threshold to detect spike onset. | Double |
| Window time (ms) | Total analysis window around spike peak (in ms). | Double |
| Slope (ms) | Time around midpoints to compute depol/repol slopes. | Double |
| N Points Filter | Number of previous points used in smoothing filter (0 = off). | Integer |
| Name | Description |
|---|---|
| Filtered signal output | Filtered version of input signal. |
| Duration (ms) output | Total spike duration. |
| Depol. slope output | Depolarization slope near mid-height point. |
| Repol. slope output | Repolarization slope near mid-height point. |
| Amplitude (V) output | Spike amplitude (max - min voltage). |
| Analysis after peak | 1 if in analysis window; 0 otherwise. |
| Min (V) output | Minimum voltage detected during window. |
| Max (V) output | Maximum voltage detected during window. |
| Mid point | Index of mid-point voltage before peak. |
| Mid point 2 | Index of mid-point voltage after peak. |
These variables store the latest computed values and are useful for logging and monitoring:
| Name | Description |
|---|---|
| Duration (ms) | Last spike's duration in milliseconds. |
| Depol. slope | Last spike’s depolarization slope. |
| Repol. slope | Last spike’s repolarization slope. |
| Amplitude (V) | Last spike’s amplitude. |
| Min (V) | Minimum voltage in the last spike. |
| Max (V) | Maximum voltage in the last spike. |
- Clone the repository or download the source code.
- Compile using RTXI's plugin build system:
make sudo make install
- Launch RTXI and load WaveformAnalyzer from the plugin menu.
The plugin buffers incoming voltage values and:
- Detects spikes based on a user-defined threshold.
- Captures the waveform around the spike peak.
- Extracts depolarization and repolarization slopes from mid-height voltage points.
- Computes duration as the time between midpoints before and after the peak.
- Outputs the results in real time.
Filtering is optional and configurable via the parameter N Points Filter.
