New Study Shows How Our Brains Chase Pleasure
In a scientific first, researchers have observed how the brain restructures itself to more efficiently repeat patterns of behavior that elicit the all-important feel-good sensation.
It’s long been accepted that humans are physiologically geared to pursue activities that reward them (some of us — teens — more than others). Normally, doing something enjoyable triggers neurons, a type of brain cell, to release a chemical called dopamine. This release causes that feel-good sensation, activates the brain’s reward system, and evokes the unconscious desire to repeat an action again and again.
“In some ways, these results are entirely expected,” said neuroscientist Rui Costa, the paper‘s senior author and the associate director and CEO of Columbia University’s Zuckerman Institute. “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.”
To the team, this meant a question had long gone unanswered: Could the brain be trained to learn the right pattern of activity normally involved in experiencing something enjoyable, and then replay that pattern at will to trigger a dopamine release?
“It’s no secret that we derive pleasure from doing things we enjoy, such as playing our favorite video game,” Costa said. “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. After repeated attempts, your brain gets better at recreating that pattern of neural activity, and you get better at the game.”
And you get the good feelings more quickly and efficiently.
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Costa and team demonstrated this through a series of experiments in mice (an animal with a surprisingly similar brain structure as humans), involving a computer program that connected the animals’ brain activity to musical notes, so that when one group of neurons switched on, a corresponding musical note played. Different patterns of brain activity yielded different combinations of notes. And when brain-activity patterns triggered the right arrangement of musical notes (arbitrarily determined by a computer), the scientists manually activated the animals’ reward systems by releasing dopamine in their brains.
The mice quickly learned which musical arrangement, when played, caused a dopamine release and the feel-good, rewarded sensation. Their brains then began to rewire themselves to follow that pattern of activation in order to play that song more often, thereby triggering the pleasure hit of dopamine.
“In essence, the mice learned to repeat the same pattern of brain activity that had been evoked previously by hearing those musical notes,” said the paper’s co-first author Vivek Athalye, of the Champalimaud Centre for the Unknown, a private biomedical research organization.
The team, which also included researchers at the University of California at Berkley, noted that these findings are a striking example of Thorndike’s Law — a long-held principle of psychology stating that actions that lead to positive reinforcement are repeated more frequently — itself a striking example of why positive reinforcement, or positive discipline, works better with children, especially teenagers, than punishment; positive reinforcement actually shapes the brain such that it works toward repeating good behavior, whereas there is no proof punishment changes the brain toward avoiding bad behavior.
The team says the implications of the finding go beyond family discipline to include explaining how we learn through repetition to “disorders such as addiction and OCD, in which the feedback loop that links an action to a reward gets thrown out of whack,” Costa said.
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