Matched Allen slice data do not resolve lower resting variability in reciprocal excitatory connections

We tested whether reciprocal excitatory connections have lower resting response variability than one-way connections in Allen Synaptic Physiology r2.1 slice data. We matched recording, ordered Cre labels, and cell layers. The test retained 54 mouse connections from 13 inferred animals and 24 human connections from five inferred donors. The reciprocal-minus-one-way log variability contrast was -0.123 in mouse, with a descriptive 95% donor bootstrap interval of -0.507 to 0.300. The human contrast was -0.253, with an interval of -0.533 to -0.023. Exact donor sign tests gave Holm-adjusted p-values of 0.575 and 0.375. Distance matching moved the human contrast to -0.039, with an interval that included zero. Neither primary test gave clear evidence. Small selected graphs, uncertain donor labels, missing variability estimates, and reverse connection detection limit inference. The result does not establish equal variability or a reliability rule across species. Code, selected records, resampling draws, a figure, source hashes, and an independent evidence check are supplied.

Allen Institute · reciprocal connectivity · synaptic variability · reliability · matched comparison · null result