Ventral striatum

The ventral striatum is the ventral part of the striatum, which is a major portion of the basal ganglia and functions as part of the reward system. It consists of the nucleus accumbens and olfactory tubercle. In non-primate species, the islands of Calleja are included. It is associated with the limbic system and has been implicated as a vital part of the circuitry for decision making and reward behaviors, including addiction.

Ventral striatum
Details
Latin	Striatum ventrale
Identifiers
NeuroLex ID	Ventral striatum
TA
TH	{{#property:P1694}}
TE	{{#property:P1693}}
FMA	{{#property:P1402}}
Anatomical terms of neuroanatomy [[[d:|edit on Wikidata]]]

Location and Structure

The Ventral Striatum is a subcortical part of the forebrain, located within the striatum, anterior to the plane of the anterior commissure. The striatum itself is subdivided into sectors along a ventromedial-dorsolateral continuum largely based upon the external connectivity of different areas. The ventral striatum includes the nucleus accumbens and the olfactory tubercle. The nucleus accumbens is made up of the nucleus accumbens core and nucleus accumbens shell, which differ by neuron populations.The olfactory tubercle receives input from the olfactory bulb but has not been shown to play a role in processing smell. In non-primate species it contains the islands of Calleja.

File:Dopaminergic system and reward processing.jpg

398x398px

Connectivity

Inputs

The ventral striatum receives direct input from multiple regions in the cerebral cortex and limbic structures such as the amygdala, thalamus, and hippocampus, as well as the entorhinal cortex and the inferior temporal gyrus. Its primary input is to the basal ganglia system. Additionally, the mesolimbic pathway projects from the ventral tegmental area to the nucleus accumbens of the ventral striatum.

Outputs

The primary outputs of the ventral striatum project to the ventral pallidum, then the medial dorsal nucleus of the thalamus, which is part of the frontostriatal loop system. Additionally, the ventral striatum projects to the globus pallidus, and substantia nigra pars reticulata. Some of its other outputs include projections to the extended amygdala, lateral hypothalamus, and pedunculopontine nucleus.

Function

The ventral striatum is closely associated with decision-making, risk, and reward, in addition to suppressing certain actions in the limbic system. It primarily mediates reward cognition, reinforcement, and motivational salience. Dopamine is its most vital neurotransmitter; thoughts of gain (monetary, emotional, or otherwise) will increase dopamine in the ventral striatum, whereas thoughts of loss decrease dopamine. This regulation of dopamine influences the impact of reward-related stimuli on behavior.

Novel, motivational, and emotion-provoking stimuli influence the activity of the neurons in the ventral striatum, probably due to inputs from the hippocampus and amygdala. The neurons that respond elsewhere in the brain to reinforcing or novel visual stimuli may mirror the inputs to the ventral striatum from the limbic system. This suggests that the ventral striatum provides a route for learned reinforcing and novel visual stimuli to influence behavior.

The ventral striatum and related structures

Dysfunction

Dysfunction in the ventral striatum can lead to a variety of disorders, most notably, depression and obsessive-compulsive disorder. Because of its involvement in reward pathways, the ventral striatum has also been implicated in playing a critical role in addiction. It has been well established that the ventral striatum is strongly involved in mediating the reinforcing effects of drugs, especially stimulants, through dopaminergic stimulation.

See also

• Striatum
• Basal ganglia
• Limbic system
• Brodmann area 34

External links

• http://www.nimh.nih.gov/images/news-items/r1_braindorsal1.jpg
• http://www.hnl.bcm.tmc.edu/fmri.html