How Dopamine Controls the Brain’s Reward and Pleasure Centers
Dopamine is one of the feel-good hormones. As defined by Encyclopedia Britannica, it’s
“a nitrogen-containing organic compound formed as an intermediate compound from dihydroxyphenylalanine (dopa) during the metabolism of the amino acid tyrosine”.
The major function of dopamine in our brain is that of a neurotransmitter in basal ganglia, corpus striatum and the substantia nigra.
High levels of dopamine in your brain will make you feel pleased, happy, most importantly, rewarded for something you’ve accomplished.
That’s why dopamine is often mentioned together with serotonin and oxytocin. All these chemicals have a positive effect on our mood and behavior.
In this article, we’re going to discuss how dopamine controls the brain’s reward and pleasure centers.
THE POSITION OF REWARD AND PLEASURE CENTERS
People function on the basis of rewards, pleasures, inhibitions, fears, and interplays between these states of mind. The levels of chemicals inside our brain related to each of these feelings vary due to different daily situations that we experience.
What’s for sure is that a high level of dopamine is closely connected with rewards. To be more precise, every time when you’re expecting a reward for something you’ve done, the dopamine levels rise.
This increase comes as a result of certain processes in the pleasure and reward centers in your brain.
In a nutshell, the brain reacts in a certain way when it’s exposed to rewarding stimuli. These reactions lead to the increase of dopamine levels, which in turn causes feelings of satisfaction and happiness.
The elements of the reward and pleasure system
What also plays an important role in the production of dopamine in the brain are two main dopamine pathways: the mesolimbic dopamine pathway and the mesocortical pathway. The former is the pivotal point in the entire brain reward system.
At this point, it’s also important to highlight the functions of the nucleus accumbens and the ventral tegmental area (VTA). The VTA is one of the key dopamine-producing parts of the brain. The nucleus accumbens, on the other hand, is one of the major centers for motivation and reward in our brain.
The mesolimbic dopamine pathway goes from the VTA to the nucleus accumbens. Since it connects a dopamine-producing area with one of the reward centers, it’s one of the most important pathways for distribution of dopamine throughout the brain.
On the other hand, the mesocorticaldopamine pathway leads from the VTA to the cerebral cortex. This area is also part of the reward system.
In the study The Orbitofrontal Cortex and Reward, Edmund T. Rolls, PH. D, explains that the feelings of reward for pleasant tastes and smells are placed in this part of the cortex.
To cut a long story short, two dopamine pathways, one dopamine-generating center and several areas that cause the feelings of reward and satisfaction make the reward and pleasure system in our brain.
The reward stimuli and experiments
Although scientists knew for ages that people reacted to many stimuli in a conditioned way, it was only in the 1950s that they were able to prove that point.
So, in 1954, psychologists James Milner and Peter Milner of McGill University conducted an experiment on rats in which they discovered the reward centers in the brain.
They placed electrodes inside rats’ brains, after which they used a lever to create electrical stimuli inside the animals’ brains. Each time they would press the lever, the same area of the brain got stimulated. This was interpreted as the feeling of reward for their effort and success.
The more time the lever was being pressed, the higher level of stimulation the rats would receive. In the notes from this experiment, it was written down that one rat got so hooked up on the stimuli and the feeling of reward for pressing the lever that this particular animal pressed it more than 7500 times.
Since the rats in this experiment kept repeating the same action over and over again to stimulate the same area in the brain, Milner and Old concluded that the animals were enjoying the entire process.
Later on, other scientists took the plunge to additionally clarify the findings of these two scientists so there were some more detailed discoveries regarding the reward areas in the brain.
To be more precise, scientists found that the area around the medial forebrain bundle is one of the most sensitive parts of the brain related to rewards and pleasure.
A huge set of nerve fibers between the hypothalamus and the VTA, the medial forebrain bundle turned out to be so sensitive for the rats that they would rather keep pressing the lever than eat food. Due to its high sensitivity, this bundle generated a more pleasant feeling than a meal.
In the video below you can see a concise presentation on the rewards system in our brain.
THE MESOLIMBIC PATHWAY
We’ve already mentioned that the mesolimbic pathway connects the VTA and the nucleus accumbens. The former is located in the midbrain and the latter is placed in the ventral striatum in the forebrain.
One of the dopaminergic pathways in the brain, this neurotransmitter highway produces and emits dopamine. The mesolimbic pathway consists of projection dopamine neurons, made of axons, which cover this entire pathway. T
he production of dopamine starts in the dopamine neurons, where dopamine-synthesizing enzymes are produced.
These chemicals travel via axons to synapses, which is where the lion’s share of dopamine is synthesized.
The mesolimbic pathway and motivation
As the dopamine is produced, it’s released into the nucleus accumbens. The level of dopamine in this pleasure and reward center regulates the level of motivation and desire for rewards in our brain.
As such, it also plays a certain role in our subjective feeling of pleasure. Hence, when the level of dopamine is high in the nucleus accumbens, people feel satisfied, motivated and fulfilled.
When they get the reward for something they’ve done, the dopamine level remains high, extending the feeling of satisfaction and exaltation.
The dysfunctionality of the mesolimbic pathway
Apart from learning and motivational salience, the role of the mesolimbic pathway is to control fear and some other processes in the brain.
All these feelings are in some way connected with the feelings of reward and pleasure. We all get accustomed to a certain level of dopamine in this part of the brain during our lifetime.
Because of that, the dysfunctionality of the mesolimbic pathway and the subsequent decrease in the dopamine levels can force us to seek the feeling of reward from other sources.
Simply put, when there’s not enough dopamine in the mesolimbic pathway, the brain tries to make up for the lack of this neurotransmitter and to stimulate the neurons responsible for pleasure and rewards.
Since we need to be motivated to get things done and lead normal lives, when the centers for motivation and reward aren’t properly stimulated, it can lead to demotivation, depression, and schizophrenia.
You can read more about different levels of motivation in the article “Maslow’s Hierarchy of Needs: Definition, Explained, Example” on our website.
Further, when the production of dopamine and the functionality of the mesolimbic pathway are deregulated, people can develop addictions or other disorders.
This is why people become addicted to gambling, drugs, sex, or any other activity that generates high dopamine levels and that intensive feeling of satisfaction and pleasure.
Dopamine sends rewarding signals
However, it’s wrong to think that dopamine itself is addictive or that it can make you feel good on itself. Being a neurotransmitter, it rather signals that something pleasant is about to happen.
In the article “No, Dopamine Is Not Addictive”, published on the Psychology Today website, clinical psychologist David Ley, Ph. D explains that dopamine is the announcer of the forthcoming pleasure. Also, it helps us learn and memorize things that cause pleasure and the release of rewarding chemicals in our brain.
For instance, when you’re about to have your favorite meal, the dopamine levels increase because your brain remembers how pleasant it is to eat that particular food.
In line with that, the mesolimbic pathway is here to inform all the areas situated next to it, as well as the nucleus accumbens that something good is going to happen to you soon.
THE MESOCORTICAL PATHWAY
The second most important dopaminergic pathway in our brain, the mesocortical pathway leads from the ventral tegmental area in the midbrain to the prefrontal cortex.
It delivers dopamine to the dorsolateral frontal cortex. This area of the brain plays a major role in emotional response, planning, abstract reasoning, motivation and cognitive flexibility and control, and other executive functions.
Because of that, it’s extremely important that it’s connected with one of the four dopaminergic pathways.
Being connected with the midbrain centers related to stimuli and rewards, the prefrontal cortex is regularly fed with the chemical information related to these feelings.
The malfunctioned mesocortical pathway
If we suffer from schizophrenia, psychoses, or anxiety, there might be flaws or abnormalities in the functionality of the dopamine stream from the mesocortical pathway to the dorsolateral frontal cortex.
A lower level of dopamine in that pathway can result in feelings of apathy or lethargy, as well as the lack of willpower.
This is so due to the hypoactive stimuli of the prefrontal cortex. Because of that, D1 receptors don’t receive enough stimulation, which is also why people with low dopamine levels can suffer from the aforementioned symptoms and other problems in cognitive processes.
In other words, when the prefrontal cortex doesn’t receive enough dopamine, many other parts of the brain subordinate to it won’t be notified on the potential rewarding experience we’re about to have. When they don’t receive that information, they can’t develop the feelings of exhilaration and excitement prior to the forthcoming reward.
As a result, such people can look and feel isolated and depressed, simply because they have low dopamine levels and their brain cannot reach that pre-rewarding state.
THE ROLE OF NUCLEUS ACCUMBENS
Situated in the basal forebrain and part of the basal ganglia, the nucleus accumbens (NAc) is the key feature of the ventral striatum. The main parts of the nucleus accumbens are the core and the shell. Both of them are important in the full functionality of this part of the brain.
The most important role of this brain element is its involvement in the reward process. To be more precise, this part is the end point of the reward circuit that starts in the VTA.
When we’re about to do something that our brain recognizes as pleasant, we’re going to experience a feeling of reward and pleasure.
In such a situation, the VTA generates dopamine hormones and other substances so as to announce that there’s going to be a reward. Those hormones are then sent to the nucleus accumbens. The end result of this process is that the level of dopamine in the NAc increases.
This part is also a vital output unit for the nervous system. In a nutshell, neurons from the nucleus accumbens travel to the basal ganglia and the ventral pallidum (VP). The latter emits neurons that go to the dorsal thalamus, where this pathway diverges to the striatum and the prefrontal cortex.
Scientists used to believe that the NAc had an important role in the reward-mediating process. Because of that, it was often connected with various addictions and their development.
Nevertheless, in-depth analyses about the connection between the nucleus and rewards led to the conclusion that dopamine doesn’t only increase prior to a reward, but it also reacts to negative stimuli.
For instance, if your brain memorized an unpleasant taste, when it gets stimulated by that very taste again, it dopamine levels will rise, as a warning. Without the nucleus accumbens, it wouldn’t be possible.
You can find out more about the entire reward pathway and its components in the video below.
THE ROLE OF VENTRAL TEGMENTAL AREA
One of the most important parts of the entire reward system, the ventral tegmental area (VTA) is situated in the midbrain, close to the substantia nigra.
The source of many different sorts of neurons, the VTA is most important for its role in the production of dopaminergic neurons. These transmitters are sent from the VTA to different parts of the brain.
Due to the character of the chemicals it produces and sends around the brain, the VTA has an important function in establishing a particular type of behavior.
The reason why this part is usually mentioned with the substantia nigra is the fact that these two elements are two key dopaminergic parts of the brain.
And while the substantia nigra is closely related to the putamen and the caudate – the two parts of the striatum – the VTA is the source of the mesocortical and mesolimbic pathways. The former ends in the cortical parts, while the latter finished in limbic regions of the brain.
The aforementioned increase of dopamine in the NAc when the brain is stimulated either by affirmative or aversive stimuli has its roots in the VTA.
Namely, the release of dopamine and its projection through the mesolimbic pathway are both triggered by the neurons placed in the VTA.
All this leads to the conclusion that the VTA is an integral part of the entire rewarding system. Because of that, some experts consider this part of the brain an important element in the addiction-developing process.
Apart from addiction, the VTA is often cited as an important factor in understanding and treading other cognitive disorders, among which schizophrenia is the most prominent one.
This is mainly so due to the fact that this disorder is connected with high dopamine levels.
Since dopamine production is activated by dopaminergic neurons in the VTA, there’s a correlation between schizophrenia and this part.
On the other hand, low dopamine levels can lead to ADHD (attention-deficit hyperactivity disorder).
Since the VTA has a huge role in dopaminergic projections, which affect numerous cognitive processes in our brain, the VTA is included in both regular and abnormal mental processes.
To cut a long story short, when the VTA doesn’t function properly, the entire brain will have difficulties in maintaining all the functions necessary for normal life.
THE LACK OF DOPAMINE – ISSUES
We’ve already discussed the most frequent disorders connected with either the lack or excess of dopamine, such as apathy or schizophrenia.
However, these aren’t the only issues that can come as a result of unbalanced dopamine levels. Since most problems occur when dopamine is low, here are some symptoms that your dopamine levels might not be on a satisfied level.
Your dopamine levels might be low if you feel frequent tremors or cramps in your extremities, as well as stiff muscles. What’s more, these symptoms are often indicators of Parkinson’s disease.
That’s why they require special attention and testing so that you start with the right therapy as soon as possible.
Further, people suffering from dopamine deficiency could suffer from constipation, the loss of appetite or fatigue.
All these symptoms can occur as the result of low dopamine. Simply put, when the pleasure centers in your brain don’t feel that the reward is coming, in form of a pleasant taste or smell, the centers that control your appetite and the digestive system won’t be inspired to eat at all.
Similarly, if you feel chronic exhaustion and low libido, your dopamine levels might not be as high as necessary for normal everyday life.
This connection is similar to the relationship between dopamine and food – if the pleasure centers aren’t notified that there’s going to be a reward for something you’d initially like to do, there won’t be any chemical support for the action in question.
Closely related to these symptoms is the lack of self-esteem and motivation to do things in your life. It’s important to know that motivation isn’t only a psychological element, but it’s deeply rooted in the chemical processes in our brain.
Dopamine is one of the major substances of the entire motivation system, which is why low dopamine levels will lead to weak motivation. If there is no chemical announcement that the reward is coming, you won’t be motivated to do what you’re planning.
Increase dopamine levels naturally
If you’re feeling any of the aforementioned symptoms, you should visit a doctor and check your dopamine.
Depending on their policy, they’ll either prescribe some dopamine supplements or recommend how to increase dopamine levels naturally.
For starters, you should change your diet. Instead of saturated fats and sugars, try to take in higher amounts of protein and fiber. They contain amino acids that will help your body produce more dopamine.
Tyrosine is one of the most important amino acids for the production of this neurotransmitter. Beef, turkey, soy, eggs, dairy products, and legumes are all rich in this amino acid, so include these ingredients to your menu.
Moreover, include probiotics in your daily routine. The brain and the stomach are closely related, which is the gut plays a major role in many chemical processes that affect the brain.
In the study “The Gut Microbiome and the Brain” conducted by Leo Galland, MD, the founder of Functional medicine, claims that some bacteria in the gut enhance increasing dopamine levels in the brain.
It’s also important to work out regularly in order to increase dopamine. Moving is one of the primary abilities that people have, which is why at least 20 minutes of physical exercise daily improves numerous physical and physiological functions.
Since continuous workout increases endorphin levels, it also improves your mood. When you’re in a good mood, your motivation is already higher. In turn, dopamine rises, as well, resulting in the better balance of this neurotransmitter.
When you’re physically active, you’ll get more sleep, which is also a prerequisite for increasing dopamine levels.
Last, but not the least, you can listen to some inspiring music that you like or binaural beats.
The latter can improve the overall state of your mind, including the levels of transmitters.
You can listen to some binaural beats in the video below.
Dopamine is one of the most important chemical elements of our brain. If it’s too low, we don’t feel enough motivation for many things that make the quality of life. In the case of high dopamine levels, we can develop some disorders that will cause too intensive behaviors.
What you can do to enhance the functionality of the nucleus accumbens and the ventral tegmental area and the overall levels of dopamine is eat well, get regular sleep, and work out regularly.
If your dopamine balance is severely damaged, you should go and see the doctor who will help you regain the balance.
Only normal dopamine levels will notify the brain to send reward signals to the pleasure centers and keep us functional and well-prepared for everyday life.
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