Failure to communicate in the brain may be behind indifference to music

Music is popular in almost all human societies, but there are some people who just don’t seem to be into it, no matter how stirring. Studying those who don’t like music can provide insight into why the rest of us do, and more general insights into human behavior.

Earlier neuroimaging studies demonstrated that music-induced pleasure may arise from the interaction between auditory neural networks and the brain’s reward networks. A recent study published in PNAS shows that people who don’t like music have lower brain activity in both these systems when they’re listening to tunes.

The study in question used functional MRI scans to track brain activity in three groups of 15 participants. One group was indifferent to music, one group had normal reactions to it, and the last group derived intense pleasure from music. Musicians were excluded from the sample, to reduce bias that might be introduced by including participants trained in producing music.

Each subject was asked to provide two pieces of instrumental music that they found emotionally pleasing (this was a particularly difficult task for the participants who don’t find music pleasurable). To supplement the music that participants provided, the researcher used music recommended by the music-matching algorithm of Spotify. The subjects’ brains were imaged via fMRI both while they listened to music and while they participated in other traditionally rewarding activities, such a gambling.

The imaging showed that people who derived less pleasure from music had comparatively lower blood flow to areas involved in the reward system of the brain when listening to music (particularly around a structure called the nucleus accumbens). There were no significant differences in blood flow to the reward regions of the brain when the participants were engaged in gambling activities. This means that there is not a fundamental problem in the reward system of the people who don’t like music—music simply doesn’t set it off.

The authors suspected that this difference might be due to reduced connectivity between the parts of the brain that interpret the music and the parts that process reward. They tested this hypothesis by checking whether there was a strong correlation between activity in reward and auditory regions. The results indicate that people who didn’t like music do have less functional connectivity, specifically between brain regions associated with auditory processing and those associated with reward. “Functional connectivity” is measured by looking at which parts of the brain are activated at the same time or in rapid succession in response to a stimulus. So, this finding means that subjects who didn’t like music showed less interaction in their superior temporal gyrus, their ventral striatum, and their nucleus accumbens in response to listening to music. This study’s fMRI findings allowed the authors to clearly demonstrate that people who don’t derive pleasure from music have a reduced communication between their auditory cortex and the mesolimbic reward system.

This work doesn’t go into cause and effect—it’s not clear whether the lowered communication between these regions causes people to appreciate music less or if their lack of appreciation leads to reduced communication. Still, these findings could help neuroscientists investigate reward responses more generally—including the responses that make the experiment’s control activity, gambling, so problematic for some.

PNAS, 2016. DOI: 10.1073/pnas.1611211113 (About DOIs).

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