Nucleus tractus solitarii (NTS) - Introduction

Introduction
I am starting with a general introduction composed of unreferenced materials (warning!) and images and with no reference to appetite.

Name
- nucleus tractus solitarii in latin
- nucleus of the solitary tract in English
- NTS

Location
- located in the brainstem along the length of the medulla with a small portion in the lower pons
Brainstem, dorsal view:

- is a part of the dorsal vagal complex (DVC), together with area postrema and dorsal motor nucleus of the vagus
- is divided into rostral and caudal regions
- has probably a very similar location in human, mouse and rat brains
Human brain, frontal plane (top left), horizontal plane (bottom left), median plane (right):

Human brain, median plane:

Mouse brain, horizontal plane:


Anatomy
- axons (white matter) run in the middle of the nucleus
- nucleus (grey matter) surround the axons
- interesting: this stands out on a stained section, which is where the name solitary comes from
- sub regions of the NTS can be related to the distribution of inputs:
- contacts from cranial primary afferent neurons related to cardiovascular, respiratory and gastrointestinal functions
- a degree of localization within the caudal region:
- many cardiovascular neurons sit near the midline of the nucleus
- many respiratory related neurons are located laterally within the nucleus

Inputs
- afferent taste information from nerves VII, IX and X
Taste receptor cell and its link to NTS:
Figure caption here:
http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=frrec&part=ch10&rendertype=figure&id=ch10.f1

- affarens from chemoreceptors in the carotid (via IX) and aortic bodies (via X)
- affarens from arterial baroreceptors from the aorta and carotid arteries called arterial baroreceptors
- chemically and mechanically sensitive neurons with endings in the heart, lungs & airways, gastrointestinal system, liver and other viscera (mostly via cranial nerves IX and X that directly enter the brainstem to form synapses within the caudal two-thirds of the NTS)

Function
- neurons mediate the gag reflex, the carotid sinus reflex, the aortic reflex, the cough reflex, the baroreceptor and chemoreceptor reflexes, several respiratory reflexes and reflexes within the gastrointestinal system regulating motility and secretion
Reflex arcs:

- also receives information about the gut wall, as well as stretch of the lungs and dryness of mucous membranes
- these first central neurons (here within the NTS) can participate in autonomic reflexes that may be as simple as two central neurons with the second neuron being an efferent or motor neuron that projects back directly to the organ such as the heart forming some of the simplest reflex pathways in the brain

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Sources
Text: Wikipedia
Images: from Google Images