all-or-nothing law

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all-or-nothing law In the functioning of the nervous system, the rule which states that the response of an axon is independent of the intensity of the stimulus, provided the stimulus exceeds the threshold intensity required to depolarize the nerve membrane. Depolarization reverses the electrical polarity from the resting potential (in which the inside of the axon is negatively charged and the outer membrane positively charged) to the action potential (positive charge inside, negative charge outside).