Connectome simulations identify a central pattern generator for fly walking.

A dynamic simulation of Drosophila ventral nerve cord connectomes identifies DNg100 as the strongest driver of rhythmic leg motor activity for walking, with a minimal three-neuron CPG.

• Why it matters: The circuit structure of a walking CPG is unknown in any animal, limiting how neural connectivity can be linked to rhythmic locomotion.
• What they did: The authors ran a computational activation screen of descending neurons and used simulated network pruning to isolate a minimal inhibitory–excitatory–excitatory interneuron circuit, then tested it across four connectome datasets.
• The result: The three-neuron circuit was necessary and sufficient for motor rhythms across all six legs, and simulations predicted DNb08 as a separate descending driver, confirmed by optogenetics in behaving flies.