Nature sub-publish found that the brain circuits of rodents may be related to negative emotions of pain

At a basic level, pain consists of two parts-feeling (the pain you feel) and emotion (the negative emotional part of pain)
.

Anhedonia is a sign of affective pain, a common feature of depression, and may increase a person’s vulnerability to opioid use disorder (OUD)

"Chronic pain exists not only at the physical level, but also at many levels.
This study proves the biological basis of emotional pain.

NIDA Director Nora D.

Volkow, MD, said: "This is a powerful reminder of psychological phenomena such as emotions.

To investigate what the emotional component of pain might be, researchers at Washington University in St.
Louis observed on the basis of previous studies that mice in pain are more likely to consume higher doses of heroin than mice without pain
.

In addition, their motivation for natural rewards such as candy tablets is also reduced

In this new study, the researchers measured the activity of dopamine neurons in the ventral tegmental area, which is part of the brain's "reward system" and is responsible for processing rewards and coordinating motivational behaviors
.

When the mice pressed the lever with their front paws to obtain candy tablets (rewards), the researchers measured their dopamine neuron activity

After 48 hours, the researchers found that the painful mice pressed the lever less frequently in order to obtain the candy, which indicated that their motivation was reduced and their dopamine neurons were less active
.

They later discovered that the reason why dopamine neurons are not so active is that the pain activates cells in a region of the brain called the medial rostral tegular nucleus (RMTg), which produces the inhibitory neurochemical GABA, which blocks dopamine.

However, when the researchers artificially restored the activity of dopamine neurons (through a process called chemogenetics), they were able to reverse the reward system that negatively affects pain and the motivation for recovery, pushing the lever sugar tablets to the pain of mice, even with painful stimuli.
Still exists
.

In other experiments, the researchers were also able to restore the activity of dopamine neurons by reversing the overactivity of GABA neurons caused by pain
.

This restores the motivation of the mice that are experiencing pain.

As far as the author knows, this is the first report that pain can promote the activity of GABA neurons and form an "inhibitory pathway" in the brain reward system through RMTg, which leads to a decrease in the activity of dopamine cells
.

"Pain is mainly studied in the surrounding areas rather than in the brain.
The purpose is to reduce or eliminate the sensory component of
pain.

At the same time, the emotional component of pain and related complications, such as depression, anxiety and lack of the ability to feel pleasure, It has been largely ignored," said study author Dr.

The author of the study, Dr.
Meaghan Creed of Washington University in St.
Louis, added: “It is satisfying to be able to show pain patients that their mental health and behavioral changes are as real as their physical feelings, and we may be able to treat these one day.
Change
.

"

Journal Reference :

1. T Markovic, et al.