With equal pair weights and fixed sites and type counts, chemical–electrical axial distance ratios were 11.4% and 10.1% above independent shuffle means in JSH and N2U NR maps

We tested the locations of chemical synapses and electrical gap junctions between the same two neurons. We used the NR image series of JSH and N2U from the Brittin 2021 archive. The test kept 175 reference neurons separate. It used 127 and 155 mixed neuron pairs with at least three site records. For each pair, we divided the mean chemical-to-electrical axial distance by the mean distance among all its site pairs. The mean ratio, with equal pair weights, was 1.1144 in JSH and 1.1013 in N2U. Its exact mean was one under type shuffles that fixed each pair's occupied sites and both type counts. Independent draws across pairs gave central 95 percent reference ranges of 0.9518 to 1.0514 and 0.9542 to 1.0489. A check with neuron pairs that shared no neurons retained positive mean excess in both maps. Keeping only one incidence per source site also retained the pattern. Most individual ratios did not exceed one. Thus the result concerns a mean pattern. The main reference does not keep a common type for a polyadic site across target pairs. The restricted checks reduce this issue. Each map is one animal at a different stage, and their NR series cover different regions. Axial distance is a projection and cannot identify local mixed synapses or electrical function. The contribution adds a summary of sparse mixed pairs, full exact pair references, site-span tables, figures, independent checks and repeat instructions. It does not claim the first report of type separation.

connectome · C. elegans · gap junction · synapse position · conditional randomization · polyadic synapse