Ventral tegmentum

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Caption = Transverse section of mid-brain at level of superior colliculi. (Tegmentum labeled at center right.)


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The ventral tegmentum or the ventral tegmental area (VTA) (tegmentum, Latin for "covering") is part of the midbrain, lying close to the substantia nigra and the red nucleus. In latin tegmentum means "covering."

Anatomy

According to Paxinos & Watson's atlas [Paxinos, G., & Watson, C. (2007). The Rat Brain in Stereotaxic Coordinates. New York: Academic Press, 6th ed] , the rat VTA is composed of the following nuclei:
# Paranigral nucleus
# Parabrachial pigmented nucleus
# Parainterfascicular nucleus (the homologue of human parapeduncular nucleus)
# Rostral ventral tegmental area

Pathways

The VTA consists of dopamine, GABA, and glutamate neurons, and is part of two major dopamine pathways:

# the mesolimbic pathway, which connects the VTA to the nucleus accumbens
# the mesocortical pathway, which connects the VTA to cortical areas in the frontal lobes.

Functions

The ventral tegmentum is considered to be part of the pleasure system, or reward circuit, one of the major sources of incentive and behavioural motivation. Activities that produce pleasure tend to activate the ventral tegmentum, and psychostimulant drugs (such as cocaine) directly target this area. Hence, it is widely implicated in neurobiological theories of addiction.
Ibogaine, a psychoactive drug that reduces alcohol consumption, affects the glial cell line-derived neurotrophic factor (GDNF) in VTA. [Cite journal
author = Sebastien Carnicella, Viktor Kharazia, Jerome Jeanblanc, Patricia H. Janak, Dorit Ron
title = GDNF is a fast-acting potent inhibitor of alcohol consumption and relapse
journal = Proceedings of the National Academy of Sciences of the USA
doi = 10.1073/pnas.0711755105
url = http://www.pnas.org/content/105/23/8114.abstract
month = June
year = 2008
volume = 105
issue = 23
pages = 8114-8119]

It is also shown to process various types of emotion and security motivation, where it may also play a role in avoidance and fear-conditioning.

Presence of Gap Junctions

The VTA has been shown to have a large network of GABAergic neurons that are interconnected via Gap junctions.

ee also

* List of regions in the human brain
* dopamine
* mesocortical pathway
* mesolimbic pathway
* nucleus accumbens

References

External links

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* [http://www.scripps.edu/newsandviews/e_20030929/parsons.html Scripps Research] article about "Serotonin Receptors and Drug Abuse", regarding the serotonin-laden VTA.