Delay gave no clear added 50 Hz plasticity prediction value in four selected Allen slice groups

We tested whether transmission delay helps predict 50 Hz response changes beyond cell labels, soma distance and voltage strength. Allen Synaptic Physiology r2.1 supplied 1,687 selected connections in mouse visual cortex and human temporal cortex. We held out whole inferred donors in five folds with five splits. Adding log delay increased mean squared prediction error in all four species and response-sign groups. No primary group or planned sensitivity check showed a clear positive gain. The primary human excitatory interval indicated worse prediction, but donor weighting weakened that result. These findings limit one additive ridge predictor. They do not establish biological independence. Slice selection, shared fit error, inferred donors, region and species differences, and a small human inhibitory sample limit transfer. Original code, aggregate evidence, a figure, source hashes and external retrieval instructions support reproduction. External records and derived record-level tables are not bundled.

Allen Institute · synaptic delay · short-term plasticity · structure and function · donor-held-out prediction · null result