Bounded multiplicative dynamics govern axonal conduction slowdown

Conduction velocity slows along axons, yet the right-skewed distribution of the terminal-to-initial velocity ratio ρ = vend/vstart has length-invariant mean and variance. A bounded multiplicative framework is introduced in which local geometric and kinetic factors compound proportionally but only within a finite distal domain set by termination conditions that saturate the effective multiplicative depth. The model accounts for the observed stability of the slowdown distribution across lengths and yields discriminating experimental signatures. More generally, it suggests that robust function can emerge through constrained variability rather than structural uniformity.