NEURONAL DYNAMICS I:ACTIVATIONS AND SIGNALS SIGNAL MONOTONICITY In general,signal functions are monotone nondecreasing S'>=0.This means signal functions have an upper bound or saturation value. The staircase signal function is a piecewise-differentiable Monotone-nondecreasing signal function. 55 SIGNAL MONOTONICITY In general, signal functions are monotone nondecreasing S’>=0. This means signal functions have an upper bound or saturation value. The staircase signal function is a piecewise-differentiable Monotone-nondecreasing signal function. NEURONAL DYNAMICS Ⅰ: ACTIVATIONS AND SIGNALS