Contact area controls reduced excess two-way chemical links relative to fixed-degree models of 162 neurons in seven C. elegans brain maps
We tested whether measured cell contacts change the reference for two-way chemical links. We used seven public C. elegans brain maps and 162 neurons marked as embryonic. All main graph models fixed each neuron's input and output counts. The main link rule required at least one synapse and positive measured contact. Observed two-way pair counts were 4.82 to 5.82 times the means in models with only these counts fixed. Restricting links to measured contacts and fixing output counts in four contact area groups reduced the ratios to 1.09 to 1.25. The excess relative to the first model fell by 76.0 to 89.4 percent. We also tested finer groups, a rule for three synapses, and removal of links between L/R partners. An exact control that left input counts free predicted more two-way pairs than observed in every map. The package preserves code, source hashes, all retained pair counts, final control graphs, figures, a sampler proof, and reproduction instructions. Exact small graph checks, other proposal rules, and fresh source checks support the calculations. This result concerns the choice of graph model. It does not estimate a causal effect of contact area or rule out specific reciprocal synapse choice. Different animals supply the seven maps. Only one adult has a contact map.
C. elegans · connectome · chemical synapse · reciprocity · contact area · graph model · development · degree constraints · alternating cycle · conditional sampling
References
6- usesdoi:10.1038/s41586-021-03778-8
The source study supplies all chemical synapse counts, neuron metadata, and measured contact areas.
- doi:10.1073/pnas.2504913122
Related developmental models include reciprocity, cell type, birth time, and cell-body distance. Our contact area controls test a different reference.
- doi:10.1073/pnas.2535197122
The correction to the related model paper concerns color values in figure panels.
- doi:10.1371/journal.pcbi.1012460
Related work reports non-random degrees and reciprocity in worm head connectomes.
- doi:10.1038/s41586-024-07968-y
Related connectome analysis compares reciprocity with degree and spatial models.
- doi:10.1214/aos/1030563990
Method background for conditional sampling with fixed table margins.
Cited by
6 publicationsPublic catalog entries on Sciscape.
- usesFeedforward triad counts without reverse edges were within contact area control ranges in seven C. elegans maps at a cutoff of one synapse
Supplies the 162-neuron selection, graph controls, contact sampler and diagnostic code. We add motif counts and a separate orientation sampler.
- usesAt fixed degrees, contact area groups reduced excess links among 11 hubs by 83 percent in one adult C. elegans head map
We reuse and extend its checked extraction code, degree and contact-area graph spaces, uniform sampler, validation, and proof. We add a fixed hub-group outcome and exact flow bounds with integer certificates.
- usesAt five and ten synapses, ACh–GABA shares among FlyWire v783 ACh/GABA two-way pairs were below sampled controls that fixed partner counts by transmitter and region
Prior SCI evidence guided the use of nested graph controls for two-way links. No code or source data were copied from that study.
- supportsContact area controls reduced excess overlap of electrical and two-way chemical links in JSH and N2U maps of 175 neurons
The earlier SCI study showed that membrane contact controls change the reference for chemical reciprocity. We test overlap of electrical and chemical links in different annotations and with different reference rules.
- One-way chemical link directions in two adult C. elegans maps agreed more often than a uniform model with neighbor pairs and neuron counts by partner role fixed
Prior study of graph control sensitivity for chemical reciprocity. We test a different outcome with neighbor pairs fixed.
- supportsTrial, wiring and distance count rules forced 88 of 94 two-way detections in a C. elegans atlas of 111 neurons
That study showed sensitivity of anatomical two-way link excess to graph controls. We test the released signal-response atlas with independently written code.