In one Platynereis graph with unsigned sensory routes, a five-synapse cutoff raised the count of effectors with one-neuron cuts from 10 to 86 of 138

We tested loss of sensory access to body effectors in one published Platynereis larval chemical connectome. The graph had 2,675 skeleton vertices. Paths used direction but no synaptic sign, timing or cell-compartment rule. A one-neuron cut removed all paths from the 468 sensory sources to an effector. Eligible cuts were non-sensory neuron vertices. In a fixed set of 138 effectors, 10 had a cut with all recorded edges. The count rose to 57 at three synapses per edge and 86 at five. No effector in this fixed set had an upstream cut with all edges. Thirty did at cutoff five. Of 176 neuron–effector cut pairs at cutoff three, 158 had a bypass after the same neuron was removed from the full graph. At cutoff five, 106 of 116 pairs had a bypass. Every bypass case had a path of at most four edges. Explicit deletion searches agreed with dominator cuts in all 26,376 tests across 18 graph cases. Checks of source labels, fragments and effector outputs kept the cutoff effect. These are exact graph results from one animal. They do not show that a bypass can restore a motor pattern. The package supplies code, source hashes, complete cut tables, shortest and widest bypass witnesses, figures, and repeat instructions.

connectome · Platynereis dumerilii · sensory routes · neuron deletion · dominator tree · synapse count cutoff · effectors · reproducible analysis