Area Postrema - Connectivity

Connectivity

The area postrema connects to the nucleus of the solitary tract and other autonomic control centers in the brainstem. It is excited by visceral afferent impulses (sympathetic and vagal) arising from the gastrointestinal tract and other peripheral trigger areas. The area postrema makes up part of the dorsal vagal complex, which is the critical termination site of vagal afferent nerve fibers, along with the dorsal motor nucleus of the vagus and the nucleus of the solitary tract. Vomiting and nausea are most likely induced by the area postrema through its connection to the nucleus of the solitary tract, which may serve as the beginning of the pathway triggering vomiting in response to various emetic inputs. However, this structure plays no key role for vomiting induced by the activation of vagal nerve fibers or by motion, and its function in radiation-induced vomiting remains unclear. Because the area postrema is located outside of the blood–brain barrier, peptide and other physiological signals in the blood have direct access to neurons of brain areas with vital roles in the autonomic control of the body. As a result, the area postrema is now being considered as the initial site for integration for various physiological signals in the blood as they enter the central nervous system.