Think you know the kind of tunes you like? It turns out that changing the patterns of activity in the brain is enough to partially alter our taste in music, according to a new study.
In a small sample of participants, researchers were able to increase or decrease how much music was enjoyed, and how eager subjects were to listen to music – all by targeting certain brain circuits with artificial stimulation.
Not only does this give us new insight into how music affects the brain, it offers researchers more clues as to how we might be able to manipulate brain activity to control issues like addiction and depression, says the team from McGill University in Canada.
For the purposes of the study, a non-invasive stimulation technique called transcranial magnetic stimulation or TMS was used to either stimulate or inhibit parts of the brain.
“Showing that pleasure and value of music can be changed by the application of TMS is not only an important – and remarkable – demonstration that the circuitry behind these complex responses is now becoming better understood, but it also has possible clinical applications,” says senior study author Robert Zatorre.
“Many psychological disorders such as addiction, obesity, and depression involve poor regulation of reward circuitry.”
Previous research has shown that pleasure from music is linked to the fronto-striatal circuits in the brain, the parts of the organ that reward anticipation and surprise. Until now though, no one had tried manipulating them.
Here TMS was applied to the left dorsolateral prefrontal cortex (DLPFC), known to modulate the function of fronto-striatal circuits and trigger the release of dopamine, an important neurotransmitter in the way our brains process reward.
Three tests were run on each of the 17 volunteers: one where DLPFC activity was enhanced, one where it was inhibited, and one where it was left alone. After each test, the participants listened to snippets of their own favourite music as well as a few clips chosen by the researchers.
They were then asked to rate their enjoyment of the music, and given the opportunity to purchase it for a price, as a way of measuring their motivation to hear it again.
Every time, stimulating DLPFC brain activity led to greater enjoyment of the music and a greater desire to purchase it. Inhibiting activity had the opposite effect.
“Showing that this circuit can be manipulated so specifically in relation to music opens the door for many possible future applications in which the reward system may need to be up or down-regulated,” says Zatorre.
Further down the line these findings could have many practical uses. Scientists are already using TMS to try and treat conditions such as depression: tweaking brain stimulation potentially offers a cleaner and safer approach than pumping the brain full of drugs.
The same type of stimulation has also been shown to help recover short-term memories, which could have applications for a range of mental illnesses.
Studies like this one, even though the sample size is relatively small, give experts a better idea of how the brain is mapped out and the sort of changes that can happen when the default wiring gets interrupted.
It also puts us one step closer to understanding why we have this unique capacity for appreciating aesthetic stimuli, like art and music – perhaps it’s more to do with chemical reactions than chord changes after all.
“[The] findings show that the functioning of fronto-striatal circuits is essential for our enjoyment of music,” says one of the team, Ernest Mas Herrero.
“This indicates that the role of these circuits in learning and motivation may be indispensable for the experience of musical pleasure.”
The research has been published in Nature Human Behaviour.