Brain waves synchronize when enjoying music, lessening depression

Anyone who has listened to music knows that it has the power to change their mood. “We listen to music to motivate us for exercise. We go to concerts and feel different after different types of music,” said Valerie Voon, a psychiatry researcher at the University of Cambridge and Fudan University.

But Voon wondered what brain mechanisms allow music to play this crucial role. In a recent study published in Cell Reports, she and her team found that the synchronization of brainwaves between three brain regions correlates with the enjoyment of music and the lessening of depressive symptoms, revealing insight into the antidepressive mechanisms of listening to music and ways to improve music-based therapies (1).

Voon and her colleagues studied 23 patients who were pursuing deep-brain stimulation for treatment-resistant depression. The patients already had electrodes implanted in two structures in the forebrain, the bed nucleus of the stria terminalis (BNST) and the nucleus accumbens (NAc). These areas play an important role in processing emotional information in the context of rewards. The team also used an electroencephalogram (EEG) to record electrical activity in the temporal cortex, where auditory information is generally processed.

We listen to music to motivate us for exercise. We go to concerts and feel different after different types of music.
- Valerie Voon, University of Cambridge and Fudan University

By playing two segments of classical music meant to evoke sadness and joy respectively, the team tested whether the music’s intended mood influenced participants’ depressive symptoms or the brainwaves in the areas of interest.

Somewhat unexpectedly, the intended mood of the music did not influence depressive symptoms, but self-reported enjoyment significantly decreased depressive symptoms, even among participants listening to the sad music. When listening to music they enjoyed, participants’ BNST, NAc, and temporal areas showed an intricate and consistent pattern of brainwaves. Theta oscillations, which are relatively low-frequency waves, in the temporal cortex seemed to coincide with increases in BNST gamma oscillations. Gamma oscillations in the BNST coupled with gamma oscillations in the NAc.

This same three-part interaction was absent among participants who reported low enjoyment of the music, so the team added a differently pitched sound to enhance the perception of the music. Participants reported higher enjoyment levels and reduced depressive symptoms after listening to music with the additional sound. The modulated music also elicited alignment between waves in the temporal cortex and the BNST for these participants.

Robert Zatorre, a cognitive neuroscientist at McGill University who was not involved in the study, has shown a similar connection between the auditory cortex and the reward system using different techniques (2). After reading this study, Zatorre said he “was super excited because, for one thing, it fits in with what we've been thinking, but more importantly because it's super rare to have the opportunity to look at physiological data from these super deep structures and people's brains.”

In future work, Voon is interested in “not just using music as some kind of background to try to modify emotion. Can you enhance it even further? That's probably the key next step for us.” She hopes to improve forms of therapy by enhancing the subjective experience of music.

“Let's remember that we're looking at a highly complex interrelated system with a lot of dynamical effects going on,” said Zatorre. “What they've been able to uncover is very good, but there's probably a lot more to uncover before we can even say that we understand the functional nature of the system.”