STA
The STA (Spike-Triggered Average) panel aligns and averages signal waveforms around spike events on a selected trigger channel. Each new spike on the trigger channel adds a waveform episode to the buffer; the displayed average converges as more events accumulate.
What You See
- Gray traces — individual waveform episodes (configurable opacity and count)
- Colored curve — the running average of all buffered episodes of a polarity: red for positive spikes, blue for negative spikes
- Hover on the red curve — tooltip showing time offset (ms) and amplitude (µV)
Controls
| Control | Description |
|---|---|
| Channel | Trigger channel for spike detection (Ch 1..N) |
| Window samples | Total window size around each spike: 2,000–100,000 samples |
| Refresh | Update interval: 50–500 ms |
| STA ± ms | Half-window in milliseconds (pre-spike and post-spike duration) |
| FIFO N | Maximum number of episodes to keep in the buffer: 10–500 |
| Traces | How many individual traces to display: 1–100 |
| Trace α | Opacity of individual traces: 0.05–0.9 |
| Mean | Show/hide the mean curve(s) |
| Band-pass | Enable band-pass filter before detection |
| f_low / f_high Hz | Band-pass cutoff frequencies |
| Polarity | Positive, Negative or Both. Each polarity is detected, buffered and averaged independently (never merged); with Both, two mean curves are drawn. |
| k×RMS | Spike threshold multiplier (default: 5.0) |
| d_min ms | Refractory period |
| RMS win ms | RMS window for σ estimation |
| Biphasic / φ lo / φ hi ms | Biphasic spike detection settings |
Status Bar
The status bar shows the current sample rate and RMS value, and, for each polarity, the number of events in the window (evt/win) and the episodes in the buffer.
Tips
- A larger FIFO N gives a smoother average. Start with 50–100 episodes.
- Increase k×RMS to 6–8 to capture only the strongest, most consistent spikes.
- Use STA ± 2–3 ms to see the typical action potential shape plus surrounding context.