Selected Allen mouse V1 electrical coupling graphs provide only one independent reciprocity loop

We tested the availability of cycle constraints on electrical coupling in Allen mouse visual cortex slices. In a stable passive reciprocal DC network, the product of voltage coupling coefficients around a loop equals the reverse product. This constraint cancels individual port resistances and survives hidden passive cells. We required two inhibitory cells, two positive electrical calls, two positive coefficients, and pulse correlation p values below .05 in both directions. The sample had 34 reciprocal edges in 30 recordings, but only one independent loop. Its products differed by a factor of 1.00490. Removing the pulse p filter gave 112 edges in 107 recordings and still only one loop. The data therefore give little support for a population test of this constraint. The single close product does not establish passive reciprocity. Finite pulse windows, state changes, measurement errors, and selection limit interpretation. We supply a graph diagnostic, a proof of its scope, source provenance, derived edges, and independent numerical checks.

electrical coupling · reciprocity · cycle space · Allen Institute · passive circuits · testability