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The mesolimbic pathway, structure and function

The mesolimbic pathway, structure and function

Experiencing things as simple as feeling joy when seeing someone we love again or feeling pleasure when having a good cup of coffee would not be possible if the different areas of our brain did not connect to each other through the neurotransmitter dopamine, which travels by sending signals through different routes. One of those routes is the mesolimbic pathway, whose function is fundamental to our survival. Want to know more about her? In this article we talk about this important pathway of the brain.

Content

  • 1 What is the mesolimbic pathway?
  • 2 Location of the mesolimbic pathway
  • 3 Main structures
  • 4 Functions of the mesolimbic pathway

What is the mesolimbic pathway?

The mesolimbic pathway is a cerebral route constituted by a set of dopaminergic neurons that connect different areas of the brain forming an essential circuit for our proper functioning. This means that dopaminergic neurons send information to each other following a route thanks to the dopamine, a very important neurotransmitter in our nervous system that allows signals to be sent between neurons related to the emotional, motor and cognitive responses of the organism to certain stimuli.

The mesolimbic pathway is one of the four main dopaminergic pathways that exist in our brain, in addition to the mesocortical route, route nigroestriatal and the tuberoinfundibular pathway. These routes have in common the connection between different parts of the brain through the transmission of dopamine.

Location of the mesolimbic pathway

The mesolimbic pathway connects the midbrain with the limbic system. This happens through the projection of dopaminergic neurons from the ventral tegmental area, in the midbrain, with the ventral striatum, among which is the nucleus accumbens. In addition, it relates to other structures such as amygdala, the hippocampus or prefrontal cortex.

Main structures

These are some of the main components of the mesolimbic pathway:

  • Ventral tegmental area: Located in the midbrain, this structure contains dopaminergic, GABAergic and glutamatergic neurons. It is one of the main dopaminergic areas and constitutes the headquarters of the body of the dopaminergic neurons of the mesolimbic system.
  • Accumbens core: Located in the ventral striatum, it is part of the limbic system and is composed primarily of medium spiny neurons. His projections come from, in addition to the ventral tegmental area, the prefrontal cortex and the amygdala. Like the ventral tegmental area, it has a very important role in brain reward processes by increasing dopamine levels by receiving signals from these areas and creating pleasant and emotional responses among many other functions.
  • Amygdala: The amygdala is an important structure formed by neuronal nuclei and located in the temporal lobe, which is part of the limbic system and whose main task is the processing and storage of emotions.
  • Hippocampus: The hippocampus is a brain region located in the temporal lobe that has a main function in the processes of memory and learning consolidation. A lesion in the hippocampus would make it impossible to create specific memories.
  • Prefrontal cortex: Located in the frontal lobe, the prefrontal cortex is the important area of ​​our brain that is responsible for cognitive control, something like a director of our cognitive processes, which include problem solving, decision making or Attention. This is projected to many areas including the nucleus accumbens.

Functions of the mesolimbic pathway

The main functions of the mesolimbic pathway are related to the experimentation of the reward or pleasure, as well as the feeling of motivation and the reinforcement or emotional learning. For example, when we feel sexual pleasure or experience motivation when going to dinner with friends, the mesolimbic pathway would have a lot to do with these sensations.

The role it plays in the motivation towards pleasure and reward since when an injury occurs in this way, the motivation to get a low reinforcement. This route is very involved in the sensation of pleasure in the face of drugs and in the experience of hallucinations and delusions.

Disorders in which it is involved

The mesolimbic pathway has an important role in different disorders such as drug addiction. When drugs that have produced high levels of dopamine in these pathways stop being consumed, there is a decrease in these levels that causes great discomfort to people who experience the symptoms that make up the abstinence syndrome.

In addition to other disorders such as depression or eating disorders, the mesolimbic pathway has a great role in the schizophrenia. Specifically it seems that this route is associated with positive psychotic symptoms, especially auditory hallucinations and delusions, with a high hyperactivity in the mesolimbic pathway, so when patients take drugs that decrease the amount of dopamine blocking dopamine receptors, positive symptoms are reduced or disappear. This not only happens in schizophrenic patients but in other people who experience psychosis such as drug-induced, mania or dementia.

Links of interest

//psychopharmacologyinstitute.com/antipsychotics-videos/dopamine-pathways-antipsychotics-pharmacology/

//www.sciencedirect.com/topics/neuroscience/mesolimbic-pathway