Dish 04 · DIV 21 · 60-channel array
Ten thousand cortical neurons, grown on glass, wired themselves into a network. Left alone it self-tunes to criticality — poised on the edge where a single spike can run away across the whole culture.
Tap the culture to poke a cascade
A dissociated cortical culture: neurons settle onto the glass and, within days, grow axons toward their neighbours. When a cell's membrane charge crosses threshold, it spikes — a bright flash — then falls silent for a refractory beat.
Faint violet threads are synapses. A spike sends charge travelling down each one; you can watch the pulse cross the gap and land on the next cell. Enough coincident arrivals, and that cell fires too.
One spike rarely stops at one. It recruits neighbours, which recruit theirs — a neuronal avalanche. Most fizzle after a handful of cells; rarely, one sweeps the entire dish. The size distribution is a clean power law.
σ → 1.00
The branching ratio σ is the average number of new spikes each spike sets off. Below one and activity dies out; above one and it explodes into seizure. At exactly one, avalanches of every size coexist — the culture holds itself there through slow homeostatic gain, nudging its own synaptic strength up when it goes quiet and down when it runs hot.
This dish measures σ live from its own cascades. Watch the readout settle toward one, then drift, then correct.
| Channel | Region | Mean rate | Bursts / min | State |
|---|---|---|---|---|
| CH-07 | antero-lateral | 3.4 Hz | 11 | ● integrating |
| CH-19 | central hub | 6.1 Hz | 18 | ● pacemaker |
| CH-28 | medial | 2.2 Hz | 7 | quiescent |
| CH-41 | postero-medial | 4.8 Hz | 14 | ● relay |
| CH-53 | edge colony | 1.6 Hz | 5 | sparse |
No footage, no recording. Every spike you see and hear is computed in the moment from a small integrate-and-fire model running on a single canvas.
Each neuron carries a membrane charge that leaks toward rest. Arriving pulses add to it; cross threshold and the cell fires, resets, and sends charge down its own synapses after a short conduction delay. A homeostatic term rescales every weight to keep the network's branching ratio near one, which is why the avalanche sizes fall on a power law — and why the culture crackles like rain rather than roars or falls silent. Each spike also opens a soft, band-limited click, pitched a little differently every time. Tap the dish and a strong stimulus injects into the nearest cell; the cascade spreads outward, seen and heard at once.