A fixed fly connectome learns to remember: the cue hides in neuronal adaptation and is read only in the brain state of learning
A spiking model built from the complete central nervous system connectome of a male fly learns to plan moves and to remember a visual cue while its wiring stays fixed. The cue is not held by persistent firing but written into neuronal spike-frequency adaptation, kept silent through a blank delay and read out by the next input. Recall works only in the brain state of learning: the same trace is nearly reversed at an untrained delay, and a lesion mimicking the Kv4 loss caused by Aβ42 rewrites the trace and its reading, while learning under the lesion is spared.