Ventral tegmental (A10) system: neurobiology. 1. Anatomy and connectivity

doi:10.1016/0165-0173(87)90011-7

Brain Research Reviews

Volume 12, Issue 2, May 1987, Pages 117-165

https://doi.org/10.1016/0165-0173(87)90011-7 Get rights and content

Abstract

The VTA contains the A10 group of DA containing neurons. These neurons have been grouped into nuclei to be found on the floor of the midbrain tegmentum — Npn, Nif, Npbp and Nln rostralis and caudalis. The VTA is traversed by many blood vessels and nerve fibers. Close to its poorly defined borders are found DA (A8, A9, All) and 5-HT containing neurons (B8).

Efferent projections of the VTA can be divided into 5 subsystems. The mesorhombencephalic projects to other monoaminergic nuclei, the cerebellum and a fine projection descends to other tegmental nuclei as far as the inferior olive. Fibers to the spinal cord have not been demonstrated.

The mesodiencephalic path projects to several thalamic and hypothalamic nuclei and possibly the median eminence. Functionally important examples are the anterior hypothalamic-preoptic area, N. medialis dorsalis and reuniens thalami. These two subsystems are largely non-dopaminergic.

A minor mesostriatal projection is overshadowed by the large mesolimbic projection to the accumbens, tuberculum olfactorium, septum lateralis and n. interstitialis stria terminalis. There are also mesolimbic connections with several amygdaloid nuclei (especially centralis and basolateralis), the olfactory nuclei and entorhinal cortex. A minor projection to the hippocampus has been detected.

The mesocortical pathway projects to sensory (e.g. visual), motor, limbic (e.g. retrosplenial) and polysensory association cortices (e.g. prefrontal). Prefrontal, orbitofrental (insular) and cingulate cortices receive the most marked innervation from the VTA. A more widespread presence of DA in other cortices of rodents becomes progressively more evident in carnivores and primates.

Most but not all projections are unilateral. Some neurons project to more than one area in mesodiencephalic, limbic and cortical systems. The majority of these fibers ascend in the MFB. Most areas receiving a projection from the VTA (DA or non-DA) project back to the VTA. The septohippocampal complex in particular and the limbic system in general provide quantitatively much less feedback than other areas.

The role of the VTA as a mediator of dialogue with the frontostriatal and limbic/extrapyramidal system is discussed under the theme of circuit systems. The large convergence of afferents to certain VTA projection areas (prefrontal, entorhinal cortices, lateral septum, central amygdala, habenula and accumbens) is discussed under the theme of convergence systems.

Anatomical studies clearly demonstrate that the VTA in general and its DA projections in particular are strategically organized to influence integrative neural function in diverse regions of the mes-, di- and telencephalon.

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Ventral tegmental (A10) system: neurobiology. 1. Anatomy and connectivity

Abstract

Neurosci. Lett.

Brain Res.

Brain Res.

Brain Res.

Brain Res.

Neurosci. Lett.

Neurosci. Lett.

Pharmacol. Biochem. Behav.

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Brain Res. Bull.

Brain Res. Bull.

Brain Res.

Brain Res.

Brain Res.

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Neurosci. Lett.

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Neuroscience

Brain Res. Bull.

Brain Res.

Brain Res.

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Brain Res.

Neurosci. Lett.

Brain Res.

Brain Res.

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Life Sci.

Brain Res.

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Neuroscience

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Brain Res.

Behav. Neurobiol.

Brain Res. Bull.

Brain Res.

Brain Res.

Exp. Neurol.

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Brain Res.

Brain Res.

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Neuropsychologia

Brain Res. Bull.

Brain Res.

Postmortem distribution of dopamine and homovanillic acid in human brain, variations related to age and a review of the literature

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J. Comp. Neurol.

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