Nucleus of solitary tract

In the human brainstem, the solitary nucleus, also called nucleus of the solitary tract, nucleus solitarius, and nucleus tractus solitarii, (SN or NTS) is a series of purely sensory nuclei (clusters of nerve cell bodies) forming a vertical column of grey matter embedded in the medulla oblongata.

Through the center of the SN runs the solitary tract, a white bundle of nerve fibers, including fibers from the facial, glossopharyngeal and vagus nerves, that innervate the SN.

The SN projects to, among other regions, the reticular formation, parasympathetic preganglionic neurons, hypothalamus and thalamus, forming circuits that contribute to autonomic regulation.

Cells along the length of the SN are arranged roughly in accordance with function; for instance, cells involved in taste are located in the rostral part, while those receiving information from cardio-respiratory and gastrointestinal processes are found in the caudal part.

Inputs

Taste information from the facial nerve via the chorda tympani (anterior 2/3 of the tongue), glossopharyngeal nerve (posterior 1/3) and vagus nerve (small area on the epiglottis)

Chemoreceptors and mechanoreceptors of the general visceral afferent pathway (GVA) in the carotid body via glossopharyngeal nerve, aortic bodies, and the sinoatrial node, via the vagus nerve

Chemically and mechanically sensitive neurons of the general visceral afferent pathway (GVA) with endings located in the heart, lungs, airways, gastrointestinal system, pharynx, and liver via the glossopharyngeal and vagus nerves.