Next time you rock out at a concert, or feel a symphony sweep over you in waves, thank your nucleus accumbens. It's most commonly known as part of the brain's pleasure center, and without it, we'd never feel joy after listening to a piece of music we really, really love. But the "why" here is an interesting question. Why does music activate the pleasure center, and why do certain types of music or certain individual songs produce euphoric sensations when others don't?
National Geographic interviewed neuroscientist Valorie Salimpoor about a study she published in the journal Science today. It's called "Interactions Between the Nucleus Accumbens and Auditory Cortices Predict Music Reward Value," and as the name suggests, Salimpoor has discovered that the types of music we've listened to in the past can actually determine the music that gives us the most pleasure.
The fact that we derive pleasure from music at all is actually linked to our prior experiences as well. Salimpoor conducted a study several years ago in which participants listened to their favorite songs and had their brain activity monitors through positron emission tomography. After listening, their brains were flooded with dopamine, providing pleasure--but this is a unique phenomenon in humans. Here's how Salimpoor explains it:
"The dopamine system is old, evolutionarily speaking, and is active in many animals during sex and eating. “But animals don’t get intense pleasures to music,” Salimpoor says. “So we knew there had to be a lot more to it.”
Salimpoor's latest experiment, using fMRI, tracked activity in multiple regions of the brain as participants were tasked with listening to 30 second samples of songs and determining whether to buy them. Choosing which songs to buy and how much to pay for them (between $0 and $2) activated different portions of the brain than simply listening. None of the 19 participants had heard the 60 songs before, but some of the songs were chosen to be similar to other music they liked. The results showed how important past experience in music can be with what we enjoy.
Whether you realize it or not, every time you’re listening to music, you’re constantly activating musical templates that you have.
"It turns out that connections between the nucleus accumbens and several other brain areas could predict how much a participant was willing to spend on a given song," National Geographic writes. "Those areas included the amygdala, which is involved in processing emotion, the hippocampus, which is important for learning and memory, and the ventromedial prefrontal cortex, which is involved in decision-making."
Slimpoor said: “Depending on what styles you're used to — Eastern, Western, jazz, heavy metal, pop — all of these have very different rules they follow, and they’re all implicitly recorded in your brain. Whether you realize it or not, every time you’re listening to music, you’re constantly activating these templates that you have.”
The nucleus accumbens uses those "templates" to predict what you'll respond to and register pleasure, hence the intense euphoria of listening to our favorite songs. The rest of National Geographic's writeup dives just how much we still have to learn about how we react to music--how deviations from our expectations provide pleasure or disappointment, and how we form them in the first place.