Dopaminergic and serotonergic pathways.

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. A neural pathway is a Neural tract connecting one part of the Nervous system with another usually consisting of bundles of elongated Myelin -insulated The brain is the center of the Nervous system in animals All Vertebrates and the majority of Invertebrates have a brain The ventral tegmentum or the ventral tegmental area (VTA ( tegmentum, Latin for covering) is part of the Midbrain, lying close to the Substantia In biological anatomy the mesencephalon (or midbrain) comprises the Tectum (or corpora quadrigemini Tegmentum, the ventricular mesocoelia (or "iter" The nucleus accumbens (NAcc also known as the accumbens nucleus or as the nucleus accumbens septi (Latin for nucleus leaning against the Septum The striatum is a subcortical (ie inside rather than on the outside part of the Telencephalon. The limbic system, or Paleomammalian brain is a term for a set of brain structures including the Hippocampus and Amygdala and anterior thalamic nuclei and a limbic It is one of the four major pathways where the neurotransmitter dopamine is found. See Chemical synapse for an introduction to concepts and terminology used in this article Dopamine is a Hormone and Neurotransmitter occurring in a wide variety of animals including both vertebrates and invertebrates

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. Pleasure is commonly conceptualized as a positive experience Happiness, Entertainment, Enjoyment, ecstasy, and euphoria, but is hard In neuroscience the reward system is a collection of brain structures which attempts to regulate and control behavior by inducing pleasurable effects Motivation is the reason or reasons for engaging in a particular behavior especially Human behavior as studied in Philosophy, Conflict, Economics The nucleus accumbens (NAcc also known as the accumbens nucleus or as the nucleus accumbens septi (Latin for nucleus leaning against the Septum Because of this, this pathway is heavily implicated in neurobiological theories of addiction. Neurobiology is the study of cells of the Nervous system and the organization of these cells into functional circuits that process information and mediate behavior The term " addiction " is used in many contexts to describe an obsession compulsion or excessive Physical dependence or psychological dependence such as However, recent research has pointed towards this pathway being involved in incentive salience rather than euphoric mood states. Incentive salience occurs when stimuli associated with drug -taking behavior begin reinforcing themselves

Clinical significance

The mesolimbic pathway is one of the major pathways targeted by antipsychotic medication. Antipsychotics are a group of Psychoactive drugs commonly but not exclusively used to treat Psychosis, which is typified by Schizophrenia. 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^[1] (particularly delusions and hallucinations). Psychosis (from the Greek ψυχή "psyche" for mind or soul and -οσις "-osis" for abnormal condition with adjective psychotic Schizophrenia ( from the Greek roots schizein (σχίζειν "to split" and phrēn A delusion is commonly defined as a fixed False Belief and is used in everyday language to describe a belief that is either false fanciful or derived from Deception A hallucination, in the broadest sense is a Perception in the absence of a stimulus. Successful antipsychotic medication is therefore thought to have its effect by blocking dopamine receptors in this pathway. Dopamine receptors are a class of metabotropic G protein-coupled receptors that are prominent in the Vertebrate Central nervous system (CNS

Dopamine neurons are lost in the mesolimbic pathway in Parkinson's Disease; however, they are lost far more quickly in the nigrostriatal pathway. Neurons (ˈnjuːɹɒn also known as neurones and nerve cells) are responsive cells in the Nervous system that process and transmit information Parkinson's disease (also known as Parkinson disease or PD) is a degenerative disorder of the Central nervous system that often impairs the sufferer's The nigrostriatal pathway is a Neural pathway that connects the Substantia nigra with the Striatum. Because deficits do not become apparent until a reduction of 80-90% in the numbers of neurons, their loss here is asymptomatic.

Other dopamine pathways

Other major dopamine pathways include:

• mesocortical pathway
• nigrostriatal pathway
• tuberoinfundibular pathway
• medullary-periventricular pathway
• incertohypothalamic pathway

References

1. ^ Diaz, Jaime. The mesocortical pathway is a Neural pathway that connects the Ventral tegmentum to the Cerebral cortex, particularly the Frontal lobes It is The nigrostriatal pathway is a Neural pathway that connects the Substantia nigra with the Striatum. The tuberoinfundibular pathway refers to a population of dopamine neurons in the Arcuate nucleus of the mediobasal Hypothalamus (the 'tuberal region' that project How Drugs Influence Behavior. Englewood Cliffs: Prentice Hall, 1996.

See also

• antipsychotic
• tardive dysphrenia

External links

• Diagram at Utah. Antipsychotics are a group of Psychoactive drugs commonly but not exclusively used to treat Psychosis, which is typified by Schizophrenia. The medical expression Tardive Dysphrenia, was proposed by the American neurologist Stanley Fahn the head of the Division of Movements Disorders of the Neurological Institute edu