Is It Worth the Chance? How Your Brain Weighs the Options

Why do we chase a positive feeling, even when we know the risks might override the reward? A research team led by Kristijan Jovanoski at Oxford University’s Centre for Neural Circuits and Behavior asked this question and found an answer: dopamine. The dopamine-releasing neurons in the brain that promote reward-seeking behavior can indirectly influence the neurons responsible for risk avoidance, potentially leading to unconstrained reward-seeking in the face of consequences. The Jovanoski study, published recently in Nature, provides exciting new insights into human behavior, particularly concerning addiction.

What is dopamine?

Dopamine is a neurotransmitter that influences human motivations and reward-seeking behavior. When we do something pleasurable, like eat something delicious, see someone we love, or win a game, the brain releases dopamine, creating a feeling of reward. That feeling is normal and helps direct human behavior. There are times, however, when it can get out of hand, with dopamine reinforcing negative behaviors like drinking alcohol, using drugs, or gambling, often leading to addiction. Dopamine systems in the brain will reward certain behaviors, despite the negative effects, something the Jovanoski study explored using fruit flies.

Fruit flies are frequently used to understand the brain, particularly how the nervous system integrates and processes information. The influence of dopamine on the encoding and updating of memories has been previously studied, and more specifically, the influence of alcohol on dopamine and adaptive memory. However, why a fruit fly would continue to go through electric shocks to attain a reward was recently unraveled.

Understanding risk and reward

This study was able to identify and manipulate specific subpopulations of dopamine neurons, map neural connections, and study how various motivational states influence different reward types. A region of the fruit-fly brain called the mushroom body contains subpopulations of neurons that use dopamine to control the seeking of reward or the avoidance of punishment. Ordinarily, punishment-encoding neurons tend to dominate over reward-encoding neurons in their activity, leading fruit flies to steer clear of an odor cue linked to an electric shock. In contrast, when the odor cue is coupled with the artificial activation of reward-encoding neurons, fruit flies are willing to endure an electric shock in their pursuit of the odor. Not only would the flies endure pain to seek a reward, but they would also give up their physiological needs, pursuing pleasure and neglecting to eat, even when hungry.

The relationship of dopamine and addiction

Insight into the relationship between dopamine and addiction comes from the study of Parkinson’s disease (PD). Parkinson's is characterized as a movement disorder consisting of slowed movement, tremors, and rigidity, caused by a reduction in dopamine levels in the brain. Previous research explored the personalities of people with Parkinson's and found they largely had non-addictive personalities and were often rigid, introverted, and slow-tempered due in part to the reduced dopamine in their system. Interestingly, once Parkinson's patients were treated with dopamine for their symptoms, some developed severe compulsive behaviors, including pathological gambling, hypersexuality, compulsive shopping, and compulsive eating. They shared the behaviors of those suffering from substance use disorders in that they continued to compulsively pursue an activity, despite knowing the harmful consequences. Yet many of the patients stopped their compulsive behaviors within a month of discontinuing medication, pointing toward the notable effect of dopamine on behavior.

Understanding the interplay between dopamine and decision-making is important for a variety of reasons, particularly in developing more effective interventions and treatments for addiction and mental health disorders. Firstly, medications targeting dopamine receptors can be better targeted for both motor disorders like Parkinson's or mental health disorders like psychosis and schizophrenia. Additionally, behavioral therapies can incorporate an understanding of dopamine’s role in decision-making, helping to address maladaptive patterns, impulsivity, and compulsive behaviors.

Future implications

There are also implications outside the world of addiction and mental health, with dopamine playing a significant role in consumer behavior and influencing how individuals respond to stimuli in the marketplace. Understanding how dopamine and reward-seeking can override risk could lead retailers to exploit impulsive buying decisions using limited-time offers, discounts, and reward systems. When consumers feel rewarded for their loyalty to a brand, they may continue to seek out that reward, even when there may be financial consequences.

The pursuit of rewards, even in the face of potential risks, is a universal human experience governed by the very neurotransmitter that shapes our motivations: dopamine. As we navigate our daily choices, perhaps it's worth considering the invisible hand of dopamine, guiding us toward pleasure and rewards while occasionally veering into the realm of risky behavior. By contemplating these questions, we open the door to a deeper understanding of our decision-making processes and dopamine's powerful role in guiding our journey through the complexities of life.