It describes a reflex in which both the afferent (sensory) and efferent (motor) axons are in the vagus nerve trunk.

It is a reflex circuit within the gastrointestinal tract (GIT).

The pathway involves the brain stem, specifically the medulla.

This reflex control of responses to gut stimuli occurs via the Nucleus Tractus Solitarius (NTS) and Dorsal Motor Nucleus of Vagus (DMNV) in the brain, collectively known as the dorsal vagal complex.

The reflex is active during the receptive relaxation of the stomach in response to swallowing, and it involves a loop from the stomach to the brain and then back to the stomach, resulting in active contraction and relaxation of the smooth muscles of the stomach.

It also promotes motility and acid secretion in the stomach.

Review: Introduction of the functions that control the GI tract (Physiology)