The nervous system distinguishes between strong and weak stimuli based on the frequency of action potentials generated. Strong stimuli produce action potentials more rapidly than weak stimuli.
Maximum frequency is limited by the refractory period of the neuron.
Action potentials in the axon are usually generated at the axon hillock. Strong depolarization in one area results in depolarization above the threshold in neighboring areas. The action potential does not travel down the axon, but is regenerated at each position along the membrane. The signal travels in a perpendicular direction along the axon regenerating the action potential. The voltage-sensitive channels in the new location will go through the same sequence previously described regenerating the action potential.