Mesolimbic pathway

Overview
The mesolimbic pathway is one of the neural pathways in the brain that links the ventral tegmentum in the midbrain to the nucleus accumbens, which is located in the striatum and is a part of the limbic system. It is one of the four major pathways where the neurotransmitter dopamine is found.

Function
The mesolimbic pathway is thought to be involved in producing pleasurable feeling, and is often associated with feelings of reward and desire, particularly because of the connection to the nucleus accumbens, which is also associated with these states. Because of this, this pathway is heavily implicated in neurobiological theories of addiction. However, recent research has pointed towards this pathway being involved in incentive salience rather than euphoric mood states.

Clinical significance
The mesolimbic pathway is one of the major pathways targeted by antipsychotic medication. Although the process is not fully understood, it has been found that disruption of dopamine function (particularly, an excess of dopamine) in this area has been linked to psychosis and the 'positive symptoms' of schizophrenia (particularly delusions and hallucinations). Successful antipsychotic medication is therefore thought to have its effect by blocking dopamine receptors in this pathway.

Dopamine neurons are lost in the mesolimbic pathway in Parkinson's Disease; however, they are lost far more quickly in the nigrostriatal pathway, and, because deficits do not become apparent until a reduction of 80-90% in the numbers of neurons, their loss here is asymptomatic.

Other pathways
Other major dopamine pathways include:
 * mesocortical pathway
 * nigrostriatal pathway
 * tuberoinfundibular pathway