“It’s no secret that we derive pleasure from doing things we enjoy, such as playing our favorite video game,” says Rui Costa, the associate director and CEO of Columbia University’s Zuckerman Institute and senior author of a paper published today in Science. His research reveals how brain activity is shaped and refined as mice learn to repeat behaviors that result in a feeling of pleasure.
But how does this relate to playing video games?
“When you move the game controller in exactly the right way to earn that high score, your brain remembers how it executed that action – which neurons get switched on, and in what pattern – so your brain can recreate that same move the next time you play,” says Costa, who is also a professor of neuroscience and neurology at Columbia University Irving Medical Center. “After repeated attempts, your brain gets better at recreating that pattern of neural activity, and you get better at the game.”
When we do something we enjoy, our neurons are triggered to release dopamine, resulting in a feel-good sensation and creating a desire to repeat that action again and again. The researchers wanted to determine if the brain could be trained to learn the right pattern of neural activity involved in experiencing something enjoyable, and then repeat that pattern to trigger a dopamine release at will.
Using mice as test subjects, the researchers developed a computer program that connected the neural activity in the brains of mice to musical notes. When one group of neurons switched on, a corresponding musical note played. Varying patterns of neural activity resulted in different combinations of notes. When neural activity patterns triggered the right arrangement of musical notes – determined by the computer program – the scientists manually released dopamine into the animals’ brains.
Through this process, the mice learned which musical arrangement would result in a dopamine release. Their brains then began to rewire themselves to play that song more often, thus triggering dopamine release more often as well. This means that through hearing these musical notes, the mice learned to repeat the pattern of corresponding brain activity that they had previously evoked dopamine release and pleasure.
“In some ways, these results are entirely expected,” says Costa. “It makes sense that the brain would mimic the feeling of reward it gets from an enjoyable experience by producing the corresponding pattern of neural activity. But it had never been tested.”
This study may be able to help us learn more about disorders such as addiction and obsessive-compulsive disorder (OCD). “If the brain’s neural-activity patterns are in overdrive, as is often the case for people with addiction or OCD, could we create a computer program that can help to retrain their brains and downshift this activity?” Costa wonders. “This is something we’re actively exploring.”