The Motivated Brain: Dopamine’s Role in Motivation
The chemical with a backstory
Dopamine. You’ve likely heard of this celebrity neurotransmitter in the news, or in the context of drugs or mental health. Dopamine is often touted as the source of pure pleasure: a survey of books on the subject show titles like Habits of a Happy Brain or Meet your Happy Chemicals. While that’s true, there’s more to the story. In reality, dopamine is implicated in many brain processes, like movement, learning, memory, sleep regulation, and even lactation. Once we look at how dopamine got its reputation and how it works, we’ll focus on one of dopamine’s important roles: motivation.
If we look back at the 1980s, we can start to understand how dopamine got crowned as the pleasure maker. The National Institute on Drug Abuse, an American research institute, began doing studies to find out how addiction works. By monitoring the brains of people using drugs such as amphetamines, they found the strong presence of you-know-who: dopamine. Thus, the link was made between dopamine and pleasure. You take a drug or engage in a pleasurable activity, and bam, your brain lights up like crazy, signals are sent back and forth, and you’re on a high.
This framework persisted for a few decades, and in fact persists in popular culture, but by the early 2010’s more and more studies had piled up that led to a new way of thinking. Dopamine is still in the picture when you eat a rich piece of cheesecake or receive a good hug, but like so many things, it’s complicated. Let’s take a look at how dopamine actually works.
What is it, and how can I get some
Your body contains over one hundred billion neurons, cells that receive information about the world and talk to other neurons about what to do with that information, like act or think. One of the ways that these nerve cells talk to each other is through neurotransmitters, which are chemical messengers that can shoot across the space between neurons. Dopamine, like some of its well-known cousins serotonin and oxytocin, is a neurotransmitter.
As mentioned earlier, one of dopamine’s important roles is motivation. A now-famous study done in 2003 showed that when rats were able to push levers to receive cocaine, their brains were flooded with dopamine before they received the drug. What happened is called a positive prediction error- the rats’ brains told them that pushing the lever would deliver something great, and once they received a surprisingly good reward, they remembered the sequence of events so they know what do for next time. Similarly, when researchers at the University of Tsukuba showed monkeys different pictures, each associated with a different reward, they found that dopamine flooded the monkeys’ brains while deciding which option to choose, and again when they made their choice.
Clearly, dopamine is needed to make decisions and to supply the motivation needed to achieve certain goals. “Low levels of dopamine make people and other animals less likely to work for things, so it has more to do with motivation and cost/benefit analyses than pleasure itself,” says John Salamone, professor of psychology at the University of Connecticut. It’s not all positive, because dopamine can be present when people are experiencing stress or pain. Researchers at the University of Miami found that dopamine was released in the brains of soldiers with PTSD when they heard the sound of gunfire. In that case, dopamine’s role is aversive, training and motivating the brain to stay away from situations that are stressful or traumatic.
New understandings of the neurotransmitter have helped researchers understand illnesses like depression and ADHD, cases where a person will have very low levels of dopamine, and therefore lowered motivation to get things done. In the case of addiction to drugs like cocaine, the brain’s reward pathway gets hijacked, making the addicted person highly motivated to keep using the drug at the expense of anything else.
A practical understanding of how dopamine plays into memory and learning can also aid the average student. "Dopamine leads to maintain the level of activity to achieve what is intended. This in principle is positive, however, it will always depend on the stimuli that are sought: whether the goal is to be a good student or to abuse drugs," says Mercè Correa, a researcher at Universitat Jaume I of Castellón. In other words, it’s helpful to have dopamine firing in your brain, within reason.
So here’s a few things you can do: first, break down your goals into small, manageable amounts. Your brain enjoys the feeling of achievement, so bring able to check things off your to-do list will give you a rush of dopamine. You can also eat food rich in tyrosine, an amino acid that is used to make dopamine. This includes protein-rich foods like eggs, legumes, turkey, and beef. Hopefully, armed with this new knowledge you’ll be motivated to go do some homework. Happy studying!
Buckley, C. (2012, November 30). UConn Researcher: Dopamine Not About Pleasure (Anymore) . Retrieved from today.uconn.edu: https://today.uconn.edu/2012/11/uconn-researcher-dopamine-not-about-pleasure-anymore/#
Phillips, P., Stuber, G., Heien, M. et al. Subsecond dopamine release promotes cocaine seeking. Nature 422, 614–618 (2003). https://doi.org/10.1038/nature01476
"Dopamine neurons mull over your options." NewsRx Health & Science, 26 July 2020, p. 195. Gale Academic OneFile, https://dc153.dawsoncollege.qc.ca:2267/apps/doc/A629892937/AONE?u=west74079&sid=AONE&xid=7e7f7973. Accessed 22 Sept. 2020
Schultz W. Dopamine reward prediction error coding. Dialogues Clin Neurosci. 2016;18(1):23-32.
Sherin JE, Nemeroff CB. Post-traumatic stress disorder: the neurobiological impact of psychological trauma. Dialogues Clin Neurosci. 2011;13(3):263-278
NIDA. 2020, June 17. The Brain & the Actions of Cocaine, Opioids, and Marijuana. Retrieved from https://www.drugabuse.gov/publications/teaching-addiction-science/brain-actions-cocaine-opioids-marijuana on 2020, September 28
Julson, E. (2018, May 10). 10 Best Ways to Increase Dopamine Levels Naturally. Retrieved from healthline.com: https://www.healthline.com/nutrition/how-to-increase-dopamine