Researchers from the Cognition and Brain Plasticity Group of the University of Barcelona and the Bellvitge Biomedical Research Institute (IDIBELL), in collaboration with researchers from the McGill University (Montreal), published a new study that defines the brain mechanisms that show the lack of sensitivity to music. The study, published in the journal Proceedings of the Natural Academy of Science (PNAS), gives hints about the importance of music from an evolutionary perspective regarding the connection between the auditory and emotion areas of the brain.
Although listening to music is seen as a satisfying activity worldwide, around 3-5% of people don’t feel good when listening to any kind of music. This condition is known as specific musical anhedonia. According to Noèlia Martínez Molina, main author of the study, “people with anhedonia don’t have problems to receive and process the information in a melody (such as intervals and rhythm) and show a positive response towards any other satisfying stimulus (money, for example) but they don’t enjoy musical stimulus”. Although this phenomenon has been known for some years, its cause was unknown
In the study, the researchers studied forty-five healthy volunteers using functional magnetic resonance imaging (fMRI). The participants were divided into three groups according to the results of a survey carried out by the same research group, the Barcelona Music Reward Questionnaire (BMRQ). During the fMRI session, participants had to listen to extracts from classical music and give evaluating scores from 1 to 4 in real time. To control the brain response for other kind of rewards, participants had to participate in monetary gambling tasks in which they could win or lose real money.
The results showed that the results of a low satisfying response to music (participants with musical anhedonia) is related to a lower activity in the nucleus accumbens, a key subcortical structure in the rewarding system. On the other hand, the activity of this structure is kept in other factors, such as money rewards.
“From an evolutionary perspective, it is interesting to see the importance of the connection between the auditory –cortical- and the emotion –subcortical- areas”, says Martínez Molina. This connection is very clear in people with musical hedonic –the ones who enjoy music- however it is low in people with anhedonia. “The link between areas ensures that music is understood as something satisfying, and ensures its importance on the evolution of a person, even when it is not clear which the biologic reward of this cultural product is” she says.
Martínez-Molina, N., Mas-Herrero, E., Rodríguez-Fornells, A., Zatorre, R. J., & Marco-Pallarés, J. (2016). Neural correlates of specific musical anhedonia. Proceedings of the National Academy of Sciences, October, 2016. https://doi.org/10.1073/pnas.1611211113