Synapse counts gave no clear link to a corrected swim-to-bend coherence contrast in 35 inputs to one leech motor neuron

We tested whether inputs with more synapses onto motor neuron DE-3R had larger changes in released coherence magnitude between swimming and left local bending. Anatomy and voltage imaging came from the same leech ganglion. In 35 matched inputs, the Spearman correlation with a repeat-corrected squared contrast was 0.0596. A two-sided count-label shuffle gave p = 0.7324. A descriptive 95% input-bootstrap interval was -0.2722 to 0.3853. A within-trial rank check gave -0.0209. The correction removes the trial variance term under independent errors and fixed state means; it does not remove spectral magnitude bias. One animal, one target, few trials, common circuit activity, uncertain matches, and behavior-specific magnitude scales limit inference. The result does not show equivalence or generalize across animals. Code, derived inputs, source hashes, all reference draws, a figure, and independent calculation checks support reproduction.

connectomics · leech · behavior contrast · coherence magnitude · synapse count · null result