Fun

A small collection of interactive tools, demos, and learning aids built by the lab. Most run entirely in your browser — nothing to install.

Dynamotype onset/offset trainer

A quiz tool to help you learn to recognize seizure dynamotypes — the characteristic onset and offset patterns of seizures. It drills you on the dynamotype taxonomy from Stacey and colleagues’ “Dynamotypes for Dummies” toolbox and atlas.

Launch the dynamotype trainer →

Based on: Sheckler C, Kish K, Walker Z, Barkelew G, Crisp DN, Szuromi MP, Saggio ML, Stacey WC. Dynamotypes for Dummies: A Toolbox, Atlas, and Tutorial for Simulating a Comprehensive Range of Realistic Synthetic Seizures. eNeuro. 2025 Oct 23;12(10):ENEURO.0200-25.2025. doi: 10.1523/ENEURO.0200-25.2025. PMID: 41027733; PMCID: PMC12549069. Code: Dynamotypes-for-Dummies.

Seizure bifurcations: onset & offset phase portraits

Seizures begin and end through distinct dynamical mechanisms, and a landmark idea in computational epilepsy — the Saggio–Jirsa taxonomy of seizure “dynamotypes” — classifies them by the type of bifurcation that switches the brain between resting and oscillating states. There are four ways a seizure can start and four ways it can stop, and each leaves a characteristic fingerprint in the EEG: a sudden jump, a gradual ramp-up in frequency or amplitude, a slowing-down before it stops, and so on.

This tool lets you see why. For each onset and offset type, the left panel shows the phase portrait — the geometry of the system’s possible states, with its fixed points, limit cycles, and flow — while the panel below shows the resulting voltage trace x(t). As the controlling parameter sweeps through its critical value, you watch the state space reorganize and the signal’s signature emerge in lockstep. The bright marker is the system’s current state; its position is projected onto the voltage axis so you can connect “where the system is” to “what the EEG shows.”

How to use it: Toggle between Onset and Offset, then either press Play or drag the timeline handle to scrub through the transition. Slow it down to study the slow regions. Click a single type to see its vector field and labeled equilibria up close, or turn on the Flow swarm to watch how a whole cloud of starting states flows through the bifurcation.

Launch the bifurcation animator →

Seizure dynamotype map explorer

The onset and offset bifurcations of the Saggio–Jirsa taxonomy aren’t separate ideas — they’re regions on a single map. This tool shows that map: a rotatable parameter sphere, shaded by the kind of dynamics that happen in each area (resting, seizing, or bistable), with the real bifurcation curves drawn as the boundaries between them. A seizure is simply a path across this map that dips out of the resting region, through the seizure region, and back.

You place an onset and an offset waypoint, and the dashed line between them is the trajectory the brain takes. The model rests unless that path actually runs through the seizure region — drag a waypoint so the line crosses the pink, and a seizure appears in the simulated EEG, with onset and offset signatures set by whichever bifurcation curves the path crosses. The EEG is generated by integrating the real fast-slow model continuously along the path, so it respects the hysteresis of real seizures: the brain only oscillates if the trajectory carries it across an onset bifurcation, not merely near one.

How to use it: Pick onset or offset, then click the sphere to drop that waypoint; drag to rotate. Watch the trace and synced spectrogram update. Use the sliders to set the rhythm frequency, measurement noise, and baseline drift, and toggle between the faithful real model and a faster normal-form approximation.

Launch the map explorer →