Train / Fruit fly multisensory circuit (FlyWire)

Two flowers: learn which one pays

With no learning inside the circuit, can echoes of the last visit and its reward be enough to follow the richer flower?

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Fly ·

Real wiringReadout from generation 0

Learning curve

press Train

No generations yet. Press Train: every generation adds a point for the best candidate, the population mean and the held out test.

Untrained (generation 1 mean)–

Best on training–

Held out, current readout–

Inside the circuit

live, current readout

readout neuronsfiring rateweight

All spikes, last 2 seconds

Saved runs

tick runs to overlay their held out curves

No saved runs yet. Train the real circuit and a control, save both, and compare their curves here.

What is being trained

Each trial the fly picks a flower. On the chosen flower it sees which side it is on (LPLC1 of that side) and, if the flower paid, tastes sugar (the sugar receptor neurons). Then the next choice comes quickly.

Beating chance needs the rule win stay, lose shift, which needs a memory of the last visit and its result. The circuit cannot learn; any memory has to be activity still echoing in the network. Expect a result near chance: that is the honest answer for a circuit without plasticity.

The score is the expected reward of the chosen flowers (0.5 is chance, 0.8 is the best possible).

Inspired by: Two armed bandit tasks in flies and mice; Rajagopalan et al. (2023) on reward learning in the fly mushroom body.

How to read the result

Fixed: the wiring, the synapse counts, the transmitter signs and the neuron model (Shiu et al. 2024). Learned: 22 readout numbers.

A rising curve alone proves little: a trained readout can often make use of any network. The evidence is in the comparison. Train the real circuit, save it, train a rewired control, and overlay the two held out curves. If the real wiring learns faster or generalises better, the specific map carries information the controls lack.

Senses: Choice time → LC16; On the left or right flower → LPLC1 of that side; Reward → sugar receptor neurons. Readout neurons: DNa01 left, DNa01 right, DNa02 left, DNa02 right, DNa03 left, DNa03 right, DNb05 left, DNb05 right, DNa11 left, DNa11 right, DNp01 left, DNp01 right, MDN left, MDN right, DNp09 left, DNp09 right, DNg13 left, DNg13 right, DNp03 left, DNp03 right, MN9 (proboscis).

Training uses a 0.25 ms simulation step (the lab uses 0.1 ms); firing rates in these circuits differ by about 2 percent. Dataset: Subcircuit of FlyWire v783: inputs HSE, HSN, HSS, LPLC1, LC4, LPLC2, LC16, ORN_DM1, ORN_DA2, sugar/water, bitter; outputs DNa01, DNa02, DNa03, DNb05, DNa11, DNp01, MDN, DNp09, DNg13, DNp03, CB0701; paths with at least 40 synapses per step. About this dataset