Did you know that some people don’t enjoy music at all?
This peculiar condition, called musical anhedonia, affects 3-5% of the world’s population.
Scientists at the University of Barcelona and the McGill University have discovered that individuals who have this condition display fewer functional connections between cortical areas responsible for processing sound and subcortical areas associated with reward. Their study consisted of 45 healthy individuals, who were gauged on their level of sensitivity to music. Afterwards, they were divided into three groups based on their sensitivity levels. The individuals listened to music while their brains were scanned using functional MRI (fMRI) to measure their response to a song. To provide a standard for interpreting their brain reward signals, participants also played a gambling game, with real monetary gains and losses.
Image Source: Morsa Images
This study revealed that during the music sessions, musical anhedonics exhibited a drop in the activity of their nucleus accumbens, a part of the subcortical area of the brain associated with reward. However, this did not necessarily indicate a failure of the nucleus accumbens, as this area was definitely active when the individual won a monetary award during the gambling task. Rather, individuals with musical anhedonia displayed fewer functional connections between cortical areas that process sound and the nucleus accumbens. Those with musical inclinations displayed improved activity and functional connectivity between these two areas of the brain.
So what motivates the brain and its connectivity?
For anhedonics, money, rather than music, was the motivating factor which activated their brains. This implies that there are different pathways which reward different stimuli. Furthermore, other cognitive disorders have also been linked to reduced brain connections. For example, children with autism spectrum disorder do not respond to the human voice, due to limited connectivity between the bilateral posterior superior temporal sulcus and nodes of the reward system, including the nucleus accumbens.
Image Source: Dorling Kindersley
The study emphasizes the significance of neural connectivity in the reward reactions of individuals.
In an interview with McGill University, Robert Zatorre, an MNI neuroscientist and one of the paper’s co-authors stated that “these findings not only help us to understand individual variability in the way the reward system functions, but also can be applied to the development of therapies for treatment of reward-related disorders, including apathy, depression, and addiction.”
Curious conditions like anhedonia often provide very useful insight on the brain’s natural functioning. Further studies of affected individuals can help reveal how music works as a motivating factor and how neural connectivity could be linked to individual incentives.
Feature Image Source: ipod by matthias.penke