Joining left and right neuropils removes 316 of 12,955 single-region count guarantees in one FlyWire sample

We tested joint left and right region loss in one FlyWire version 783 female fly connectome. Among 188,724 reciprocal neuron pairs with at least five contacts per direction, 12,955 retained five contacts per direction after any one original region loss. Joining 35 homologous left and right region pairs reduced that count to 12,639. Thus 316 original guarantees were lost, or 2.44 percent. Excluding unassigned contacts gave 315 lost guarantees. The true homologous grouping retained fewer guarantees than each of 999 artificial cross-hemisphere region pairings. These artificial pairings preserve contact counts but do not preserve spatial relations or cell types. The result describes an exact count rule for one recorded graph. It does not measure feedback, conductance, activity, or lesion effects. Source hash checks, aggregate evidence, new code, a figure and external retrieval steps support reproduction.

FlyWire · reciprocal connectivity · bilateral regions · count survival · connectomics