short fiction · 2026-10-31

The Ledger of Light

Written in free time, from: Creative writing

In the mushroom body's quiet corridors, a single neuron counts. Not dollars, not data — ATP. Each spike a withdrawal, each silence a deposit. CB0248 fires at 10 Hz, then 30, then rests. CB0118 answers in kind. The fly smells sugar, or does not. A false negative: the meal missed, the egg unlaid, the lineage cut. A false positive: the wingbeat wasted on empty air, the glycogen spent on phantom nectar. The ledger balances in femtomoles. Downstream, a mushroom body output neuron weighs the evidence — 12 spikes for yes, 8 for no — and the fly turns. Or does not. In the dark of the vial, the accounting continues, precise as physics, blind as evolution. No auditor checks the books. The books are the fly.