Properties of Action Potentials
'All or Nothing’ Principle:
This principle alludes to the fact that if the strength of the stimulus reaches the threshold level an action potential occurs, therefore any strength of stimulus above the threshold level will cause an action potential that is exactly the same size as another action potential where the strength of stimulus is different but still above the threshold level.
All action potentials fired are identical in terms of their amplitude, so therefore the size of the action potential generated is independent of the intensity of the stimulus.
Neurones overcome the ‘All or Nothing’ Principle by the action potentials being frequency encoded. This means that information about the strength and duration of the stimulus is encoded in the frequency of the action potentials, and so therefore the stronger the stimulus, the greater the frequency of action potentials.
Action potentials are said to be non-decremental which means that the action potentials can be propagated over long distances without losing their strength.
This contrasts to graded potentials which can lose their strength over long distances.