A one-pole shape bound fails for 13 of 916 screened Allen response fits despite free time scaling

We tested a necessary shape bound for a single exponential current-to-voltage filter in Allen cortical slice data. Temporal variance and third cumulant give a bound that is unchanged by separate time scaling of the two response modes. It failed for 24 of 1543 valid paired fits and 13 of 916 fits after a screen for expected parameter limits. A factor 1.10 allowance in each dimensionless shape value left five screened failures. Numerical integration, independent minimization, constructed controls, and a repeated raw-data run checked the calculation. Most fits passed this weak condition. Tail extrapolation, separate clamp states, uncertain shape error, and the one-pole assumption limit interpretation. The result does not reject passive spatial neurons or establish generalization. The package provides a proof, original code, aggregate results, a figure, and external retrieval instructions. Source records remain outside the bundle.

Allen Institute · synaptic filtering · temporal shape · one-pole model · cumulants · scale invariance