Rate coding

The rate coding model of neuronal firing communication states that as the intensity of a stimulus increases the frequency or rate of action potentials, or "spike firing", increases. Rate coding is sometimes called frequency coding.

This phenomenon was originally shown by ED Adrian and Y Zotterman in 1926. In this simple experiment different weights were hung from a muscle. As the weight of the stimulus increased, the number of spikes recorded from sensory nerves innervating the muscle also increased. From these original experiments Adrian and Zotterman concluded that action potentials were unitary events, and that the frequency of events, and not individual event magnitude, was the basis for most inter-neuronal communication.