Cloche · Flies on a Windowsill

Click a fly to select it · click the counter to drop sugar · drag to orbit · scroll to zoom

Loading the connectomes…

Two brains: the FlyWire female (139,255 neurons, 10 MB) and the Janelia male (166,700 neurons, 21 MB). Cached after the first visit.

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Brain FlyWire v783

Neurons active–

Spikes per second–

MN9 · proboscis–

Grooming DNs–

Giant fibre–

Brain speed–

Resting. Every neuron is silent until you do something.

Specimen

Doing–

Hunger–

Status–

Sugar neurons–

Bitter neurons–

Johnston's organ–

Looming detectors–

Fruit receptors–

Vinegar receptors–

Kenyon cells firing–

Descending, left / right–

LC10a · sees her–

P1 · courtship–

pIP10 · song–

JO-A · hears song–

vpoDN · accepts–

oviDN · lays–

Windowsill

Adults–

Brood–

Brains–

Wipes every fly, its learning, the brood, the drops and the smells, and starts a fresh windowsill with a new female and male.

Memory no synapses changed

Fruitunknown

Vinegarunknown

Read straight from the mushroom body: how far this smell's Kenyon-cell synapses onto avoidance neurons have been weakened by reward, against those onto approach neurons weakened by punishment. Feed it sugar while a smell is on the base and it learns to like the smell; bitter, and it learns to avoid it. Saved in this browser.

What is real

Real: the wiring. Females run every proofread neuron of the FlyWire female brain; males run the Janelia male central nervous system, brain and nerve cord. Every connection of five or more synapses, its sign and strength, and the integrate-and-fire dynamics from Shiu et al. Reflexes fall out of that: sugar drives MN9 and the proboscis extends, bitter cancels it, a shadow fires the giant fibre, a poke drives descending neurons. Smells arrive through the real receptor neurons as a sparse, smell-specific set of Kenyon cells, and learning is the fly's own rule: dopamine neurons of one mushroom-body compartment weaken that compartment's Kenyon-cell synapses. Courtship runs on the male's real wiring: seeing a female drives his LC10a neurons, the P1 cluster and the pIP10 song command follow; she hears through JO-A and her vpoDN acceptance neuron answers; a mated female's oviDN neurons command each egg.

Added to the model: rate-dependent spike-frequency adaptation so driven loops settle; a slow brain-wide activity ceiling; neuromodulatory synapses scaled to a tenth; the antennal lobe's local neurons forced inhibitory where the data left their transmitter unpredicted; the male's taste neurons sorted into sugar and bitter by matching their downstream cell types to the female's; and a quiet resting hum in the sensory neurons.

Staged: the bodies. No muscle model. Firing rates are smoothed onto rigged low-poly flies. Walking to food, the flights, the hunger clock, the mounting itself, the "mated" flag and the trigger that drives oviDN on fruit are hand-written. Eggs, larvae and pupae have no brain: the larva's connectome is a different animal. The connectomes decide what the flies do; the page decides how that looks.

Connectomes: FlyWire v783 (female), FlyWire Consortium, Princeton University, CC BY 4.0. Dorkenwald et al. 2024 and Schlegel et al. 2024, Nature; male CNS v1.0, Janelia FlyEM, CC BY 4.0. Mushroom-body map: Aso et al. 2014. Neurotransmitters: Eckstein et al. 2024. Model: Shiu et al. 2024, Nature, code MIT. The simulation runs entirely in your browser; nothing is sent anywhere.