Feedforward triad counts without reverse edges were within contact area control ranges in seven C. elegans maps at a cutoff of one synapse
We tested chemical graphs of 162 embryonic neurons from seven C. elegans brain maps. An exact feedforward triad had three forward edges and no reverse edges. At a cutoff of one synapse, its count was within the central 95 percent range of every control with four contact area groups. Each control fixed all neuron input and output degrees, allowed edges only at measured contacts, and fixed each source's output count in each area group. Partial feedforward loops allow extra reverse edges. Their counts were 1.20 to 1.33 times control means and above every upper range limit. Contact area controls reduced their excess over degree controls by 60.9 to 68.3 percent. A separate control fixed every connected pair, every reciprocal pair, and all degrees. In eight maps, partial loop counts were then 1.010 to 1.027 times control means, but still above their upper range limits. The three-synapse check gave the same distinction under four area groups. The package includes code, figures, control scores, final graphs, source hashes, sampler proofs, and repeat instructions. The ranges describe model graphs, not animal populations. The fixed-pair control preserves biological choices as well as geometry. These results do not show random wiring or identify a causal role for contact area.
Caenorhabditis elegans · connectome · feedforward loop · induced triad · physical contact · contact area · graph reference · reciprocal edge · conditional sampling · graph orientation
References
7- usesdoi:10.1038/s41586-021-03778-8
Supplies the biological contact, chemical synapse and neuron measurements.
- usesContact area controls reduced excess two-way chemical links relative to fixed-degree models of 162 neurons in seven C. elegans brain maps sci:sha256:cb6521f9a7ca217bc005add76a9ca7d31d146de09e7d928cda907d4b662a6988
Supplies the 162-neuron selection, graph controls, contact sampler and diagnostic code. We add motif counts and a separate orientation sampler.
- doi:10.1126/science.298.5594.824
Gives the classic network motif framework. Our maps and tests differ from its full study.
- doi:10.1371/journal.pcbi.1012460
Gives prior motif inference work on connectomes and explains dependence on graph models.
- doi:10.48550/arXiv.1902.06103
Gives prior work on fixed-degree graph orientations and cycle reversals.
- doi:10.1137/16M1087175
Gives graph-space and fixed-degree sampling methods.
- doi:10.1186/s12915-026-02641-4
Gives recent signed motif work. Our unsigned topology test does not test its sign-specific conclusions.
Cited by
3 publicationsPublic catalog entries on Sciscape.
- In a test between two adult C. elegans maps, shared sites gave no clear extra target connection score after contact and neuron controls
Shows that measured contact controls change graph motif results. The current analysis tests site grouping with the full source connection matrix fixed.
- With neuron totals fixed, an early wiring model gave a higher forward synapse fraction than each of two adult C. elegans maps
This prior SCI study tests feedforward triad counts in the same maps under graph controls. Our question concerns broad-class synapse fractions across development.
- supportsMotor partner clustering in one dauer C. elegans map was within sampled ranges under degree and contact area constraints
This earlier SCI study shows that measured contact controls and exact motif definitions can change inference in a different C. elegans panel. We extend that question to motor partner clustering in a dauer map. We do not reuse its code or extracted data.