Positive reciprocal responses admit passive circuits when self-responses and wiring are free

We tested whether passive circuit restrictions add a constraint beyond reciprocity for positive responses between different cells. A constructive proof shows that any finite cycle-consistent response set admits a stable passive circuit after positive cell gains, if self-responses and wiring are free. A large diagonal completion gives positive leaks and conductances. We applied the method to 21 selected worm pairs with electrical contacts in at least one of two adult anatomy maps. The smallest uniform response change factor was 1.081936, which repeats a prior reciprocity result. We add passive circuits that attain this factor. Three different circuits fit the same changed responses. Eighteen constructions and 60 synthetic checks passed. Nine pairs with contacts in both maps had no cycles and needed no response changes. The construction uses dense wiring and large unmeasured self-responses. It does not fit measured anatomy or time courses, estimate response error, or show passive physiology. Original code, a proof, aggregate evidence, source hashes and retrieval instructions support reproduction. External records remain outside the bundle.

passive circuit · identifiability · reciprocity · cell gains · C. elegans · connectomics · matrix completion