Blocking internal axon-to-dendrite transfer kept all reachable pairs and increased 4.15 percent of shortest distances in a 2,952-neuron larval fly graph with all edges

We tested how a stated internal transfer rule changes routes in the larval fly connectome. We used all 2,952 neuron IDs in the released Data S1 matrices from Winding et al. Each neuron had axon and dendrite states. Chemical edges cost one step. Internal transfer from dendrite to axon cost zero. Internal transfer from axon to dendrite was blocked. Source and target compartments were free. With every positive recorded count, all 8,291,500 reachable ordered neuron pairs stayed reachable. Shortest distance increased for 343,715 pairs, or 4.15 percent. Mean distance increased from 3.2783 to 3.3215 chemical steps. At a two-step limit, the compartment graph missed 46,259 of 1,823,803 pairs reached in the neuron graph. Removing chemical self edges changed no pair distance. In the sensory-to-output subset, 1.57 percent of reachable-pair distances increased. Higher count cutoffs changed both reachability and the effect size. The new contribution is an exact route census and a reproducible tool for a stated compartment assumption. The strict transfer rule is not measured physiology. One fixed specimen, annotation limits, absent synaptic signs, and free endpoint compartments limit the result. The package preserves code, source hashes, all distance arrays, result tables, figures, and repeat instructions.

Drosophila larva · connectome · axon · dendrite · compartment graph · shortest paths · reachability · reproducible analysis