How much of fly walking is written in the wiring?

2026-09-29

AI Summary

This study addresses how specific wiring in the Drosophila connectome shapes motor output. Using computational neuroscience modeling, we simulated the fly leg motor system and compared multiple rewired networks under fixed synaptic weights and preregistered experimental criteria to systematically examine, for the first time, the differential contributions of wiring features to rhythm generation and antagonistic coordination. Our results reveal that biological wiring specificity is not essential for sustaining rhythmicity but serves as a critical determinant of antagonistic coordination, which is particularly pronounced at the thoraco-coxal joint. Furthermore, premotor input allocation proves essential for maintaining this mechanism. By elucidating the circuit basis of Sherringtonian reciprocal inhibition, this work establishes a novel paradigm for understanding the relationship between neural wiring and motor function.

Abstract

Connectome models of the fly nerve cord generate walking-like motor rhythms, but oscillation alone does not show that the specific wiring matters. Here we provide, to our knowledge, the first test of which features of motor output depend on the specific wiring. We simulated the leg motor systems of two independent Drosophila connectomes, with synapse counts as fixed weights and glutamatergic synapses treated as inhibitory, and compared each with six families of rewired networks that preserve progressively more of its structure, using pre-registered criteria. We find that rhythm is generic but antagonist coordination is not: many rewired networks were more rhythmic than the real ones, yet the real wiring coordinated antagonistic motor pools more strongly than every rewired network, most of all at the thorax--coxa joint. We trace this specificity to how premotor input is allocated between antagonistic pools. Both connectomes carry Sherrington's reciprocal innervation---neurons that excite one pool inhibit its antagonist---and no rewired network does. Reassigning premotor inputs between the pools abolished coordination even when motor neurons' typical input strength changed little (all pre-registered criteria met in one connectome; same direction in the other). Coordination, not rhythm, therefore reveals whether a connectome model's wiring matters.

Problem

• connectome
• Drosophila
• motor coordination
• walking
• neural wiring

Innovation

• Connectome simulation
• Motor coordination
• Rewired networks
• Reciprocal innervation
• Premotor input allocation