Figure 4 - Electrical stimulation of intrinsic nerves in circular smooth muscle strips.

Stimulation results in phasic contraction after a variable delay. The latency to onset of this contraction increase progressively in strips taken from more aboral segments of the smooth muscle esophagus. This demonstrates the existence of an "intrinsic latency gradient" of contraction along the esophagus, which contributes to the generation of a peristaltic wave.