Brain state locks silent memories in a trained fly connectome

A fixed wiring spiking model of the whole male Drosophila melanogaster central nervous system (167,106 neurons) stores a visual cue as silent adaptation trace.

• Why it matters: It is unknown whether a fixed insect connectome can learn and what the resulting memories consist of, including how they depend on brain state.
• What they did: The model was trained to plan moves and remember a visual cue; spikes wrote the cue into neuronal adaptation, which was read out on the next input.
• The result: The trace is enriched for transcripts of a calcium-activated potassium channel, is recalled only in the learning brain state, and a disease-like potassium-current loss rewrites the trace and alters its readout.