Ventral tegmentum

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Brain: Ventral tegmentum
Transverse section of mid-brain at level of superior colliculi. (Tegmentum labeled at center right.)
NeuroNames hier-512

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."

Contents

Anatomy

According to Paxinos & Watson's atlas[1], the rat VTA is composed of the following nuclei:

  1. Paranigral nucleus
  2. Parabrachial pigmented nucleus
  3. Parainterfascicular nucleus (the homologue of human parapeduncular nucleus)
  4. Rostral ventral tegmental area

Pathways

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

  1. the mesolimbic pathway, which connects the VTA to the nucleus accumbens
  2. 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.[2]

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.

See also

References

  1. ^ Paxinos, G., & Watson, C. (2007). The Rat Brain in Stereotaxic Coordinates. New York: Academic Press, 6th ed
  2. ^ Sebastien Carnicella, Viktor Kharazia, Jerome Jeanblanc, Patricia H. Janak, Dorit Ron (June 2008). "GDNF is a fast-acting potent inhibitor of alcohol consumption and relapse". Proceedings of the National Academy of Sciences of the USA 105 (23): 8114-8119. doi:10.1073/pnas.0711755105. 

External links

Wikipedia content modification information:

  • This page was last modified on 11 October 2008, at 21:45.

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