With target groups fixed in 2 micrometre cubes, sites within 0.5 micrometres had extra target overlap in six of eight C. elegans brain maps

We tested whether nearby chemical synapse sites share target neurons beyond a local target-group reference. We used 14,296 retained sites in eight C. elegans brain maps from different animals. The primary panel had 7,891 site pairs and 482 source-neuron records. We assigned whole target groups among sites with the same source, 2 micrometre cube, and target number. This fixes local target counts, complete groups, and target number at each coordinate. Six maps had higher mean target-set Jaccard overlap after Holm correction across eight tests. The two adult excesses were 2.89 and 3.00 percentage points. The spatial limit removed 89.7% and 88.3% of the excess above a reference without a spatial limit. Adult excesses remained at 1.19 and 1.05 points with 1 micrometre cubes. An exact assignment sampler added a target-skeleton proximity rule in an exploratory check. A 1 micrometre rule left 1.77 and 1.96 extra points in panels of 106 and 109 adult sources. A 0.5 micrometre rule left no clear excess in smaller panels of 18 and 34 sources. Only 3 and 13 source scores had nonzero sampled variance in those smaller panels. Thus, spatial rules and assignment freedom change the result. The study measures fixed-map anatomy. It does not establish a synapse-recognition mechanism, neural function, or a population age effect. The package contains source code, derived data, source hashes, random scores, figures, and repeat instructions.

Caenorhabditis elegans · connectome · synapse location · polyadic synapse · target group · spatial control · conditional randomization · exact assignment · neurite proximity · reproducible research