Soma distance reduced delay error but gave no clear 50 Hz change gain in fixed tests of mouse cortical connections with separate donors

We tested whether soma distance helps predict rapid response change in cortical connections. We used Allen Synaptic Physiology r2.1 and fixed ridge models with separate donor folds. The primary sample had 1,033 mouse connections from 413 inferred donors. Models controlled for cell labels, recording data, cortical depth, measurement counts and measured postsynaptic potential strength. Adding distance increased initial 50 Hz change error by 2.18%. The descriptive 95% donor resample range for error reduction was -4.25% to -0.27%. A delay control on 1,032 connections gave a 6.24% error reduction, with range +2.06% to +9.86%. Late change gave a 0.05% error increase. Planned checks gave no clear initial-change gain. An added check used identical connections and folds for delay and initial change. It kept the same qualitative result. These tests limit a soma-distance prediction rule. They do not establish that distance has no biological role. The data are selected slice recording graphs, not a complete connectome. The package preserves original code, source versions and hashes, predictions, errors, fitted states, figures and repeat instructions. Source measurements and upstream software remain external under their source terms.

structure and function · soma distance · short-term plasticity · synaptic delay · cortical circuits · donor validation · Allen Synaptic Physiology