Cyclic Inhibition

Cyclic inhibiton may be best explained by way of an example. Given the triphasic rhythm of segmental interneurons, if cells in the 0 degree phase begin to produce action potentials in response to tonic excitation, these cells would inhibit cells in the 240 degree phase. The inhibition of the 240 degree phase cells would allow the 120 degree phase cells to recover from inhibition received from the 240 degree phase cells, prior to when the 240 degree phase cells were turned off. Now that the 120 degree phase cells are free from inhibition, they can respond to tonic excitation and postinhibitory rebound to produce action potentials which will silence the 0 degree phase cells. The cycle would consist of a burst of action potentials in sequence from 0, 120, and 240 degrees.