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According to new research from UCL Institute of Neurology, the release of the brain chemical dopamine influences how people make choices by affecting expectations of pleasure.

The study, which was recently published in Current Biology, confirms that dopamine not only plays an important role in how people make more complex decisions, but also how human expectations are formed. The study offers new insight into how pleasure expectation can go awry, such as with drug and alcohol addiction.

“Humans make much more complex decisions than other animals, such as which job to take or whether to start a family,” said the lead author of the study.  “We wanted to understand the role of dopamine in making these types of decisions.”

The role of the neurotransmitter dopamine in reward-seeking behavior is well understood through animal studies; however, its role in human behavior is much less understood. The results from the study indicate that when faced with having to consider options when making real-life decisions, dopamine did play a role in “signaling the expected pleasure from those possible future events.” (Science Daily). This signal is what humans use to make decisions. It makes sense that this is why the brain can get stuck in the pleasure-seeking cycle when drugs are involved.

A recent grant provided through the American Recovery and Reinvestment Act (AARA) awarded almost nine million dollars to the University of California San Diego. The brain study, which will use sophisticated gene-mapping tools and imaging technology to collect data about brain development in children, will be looking for the biological bases of differences in human behavior.

“The impact of the study is likely to be very broad,” said Terry Jernigan, Ph.D, project leader and professor at UC San Diego’s Center for Human Development. Jernigan hopes the brain study will accelerate the investigation of genetic risk factors and gene-by-environment interactions that contribute to disorders, such as substance abuse. “It will provide information that could help to enhance education, improve early detection of mental disorders, and identify targets for early interventions that may prevent negative outcomes, such as addiction and mental disorders.”

The brain study, which is called PING (pediatric imaging, neurocognition and genetics), would essentially create a database, or map, depicting the genomic landscape of the developing brain. The study will include 1,400 children between the ages of 3 and 20. The potential outcome of the study will make it possible to search for links between genetic variation and developing patterns of brain connectivity. It will shed light on how genes influence brain development and how it can go awry in certain individuals or following certain environmental events, making early intervention and prevention a more attainable goal.

The grant was awarded by the National Institute on Drug Abuse (NIDA), a part of the National Institutes of Health (NIH).

Our brains are hard-wired to seek reward. If we make a good decision, our dopamine levels go up. This tells our brain, good decision, do it again next time. It literally changes the anatomy of the brain to repeat the action. This strengthens certain connections and decreases others so that this desirable increase in dopamine will happen again. This is how an addiction is formed

Dopamine plays an important role in our ability to handle stress, be motivated, and create an overall sense of well-being. The use of drugs or alcohol raises the level of dopamine, resulting in an artificial “feel-good” sensation. When the brain’s levels of dopamine are in natural flux, we experience survival instincts: the need to eat, reproduce, or be a part of a group. In fact, our motivation to do anything: to feel good, to experience a sense of well-being, is controlled by the healthy fluctuation of dopamine levels. As a way of regulating itself, the body will also deactivate dopamine receptors, so that we don’t experience the need to eat or feel good all of the time. In doing this, the brain makes sure that the reward system that has enabled us to survive and evolve over millions of years is not disrupted.

However, chronic use of drugs or alcohol causes the brain to become accustomed to external stimulation of neurotransmitters and receptors. This interrupts the natural ebb and flow of the body’s chemical production. Chronic use over-stimulates the receptors until they are damaged, unable to support themselves with their own chemicals, and the number of neurotransmitters is reduced. As a result, an individual will experience depression, anxiety, inability to handle stress, withdrawal symptoms, intense cravings, and deeper addiction.

It isn’t just drug and alcohol addiction and dopamine that are related. Dopamine is thought to play a role in other conditions such as obesity, gambling, Parkinson’s disease and ADHD. The National Institute on Drug Abuse is researching different types of vaccines that will may eventually be able to prevent a drug, such as cocaine, from entering the brain and overloading the dopamine system and setting into motion a vicious cycle. Currently, protocols like Neurotransmitter Restoration address the re-balancing and repair of the brain and its reward cycle.