Figure 1.

Vagal afferent neurons. The gastrointestinal tract is densely innervated by the vagus nerve and its mucosal endings acts as chemosensory terminals detecting nutrients and hormones, whereas the IGLEs are anatomically concentrated in muscle layers and detect gastrointestinal stretch. The cell bodies of the afferent fibers are located in the nodose ganglia and the signals from their terminals are relayed to the NTS. The PBN, in turn, receives ascending inputs from the NTS and coordinates meal termination. IGLEs, intraganglionic laminar endings; NTS, nucleus tractus solitarius; PBN, parabrachial nucleus.