Target pair count agreement in two adult C. elegans brain maps was 26 percent above controls with fixed counts in 2 micrometre cubes

We tested whether chemical synapse target groups agree between two adult C. elegans brain maps beyond their weighted connection counts. We used 180 identified neurons from Witvliet et al. (2021). A group has one source and two distinct targets. The agreement count sums the product of each group's site counts in the two maps. The recorded count was 10,527. Random maps kept every source-to-target site count and every site target count fixed. Their mean was 4,978.54. When target counts were also fixed within each source and 2 micrometre cube, the mean was 8,363.43. The recorded count was 25.87 percent higher. No random count reached it in 2,000 saved draws per model. Local constraints removed 61.0 percent of the whole-source excess. The ratio stayed above one after merging records at one source node (1.195), removing both RIA neurons (1.162), or giving each source equal weight (1.096). Randomizing only one adult also left a local excess. In contrast, the 938 distinct shared groups were near the whole-source and 2 micrometre random means of 946 and 930. The 5 micrometre control gave a smaller mean of 908. Thus excess distinct-group overlap depended on the control. The result supports shared anatomical group frequencies in these two maps under the stated models. Fine contact geometry and annotation choices remain possible causes. The test does not match individual sites across animals or establish shared release, neural activity, or population variation. The package preserves code, source URLs and hashes, count tables, random draws, figures, exact small-state checks, independent audits and repeat instructions.

Caenorhabditis elegans · connectome · polyadic synapse · target groups · cross-animal agreement · fixed margins · spatial controls · reproducible research