A 0.55 ms relay-time range permits either route order in four selected Allen excitatory circuits

We tested whether stored response delays fix the earlier of two excitatory two-step routes in Allen Synaptic Physiology r2.1. Two mouse VisP pairs and two human TCx pairs met the selection rules. Their delay-sum gaps were 0.233 to 0.543 ms. In an additive model, if each edge error is at most e and both relay times lie in an interval of width R with a common lower limit, the route-time difference has exact limits g minus 4e minus R and g plus 4e plus R. A relay-time range of 0.55 ms permits both orders in all four pairs with edge delays fixed. At equal relay times, an edge error bound of 0.05 ms preserves all four stored orders. Independent excitatory cell labels retain both mouse pairs and remove both human pairs. The model bounds passed exhaustive vertex checks. The sample uses three recordings; the human pairs share edges. No relay times or actual indirect responses were measured. These are conditional sensitivity results, not evidence for neural route switching. Original code, proof, aggregate results, figure, source hashes and external regeneration steps are supplied. External records are not bundled.

Allen Institute · parallel routes · synaptic delay · relay time · interval uncertainty · circuit timing