Musical pleasure mediates dopaminergic learning: an fMRI study

Abstract

Music has been important to every culture in recorded history, and is widely considered among the most pleasurable things in the world. This relationship seems to have its root in the brain's reward system, where enjoying music corresponds to dopamine release. Yet according to reinforcement learning theory, this system is primarily involved in orienting towards biologically advantageous rewards, such as food and sex, to optimize behaviors for survival and reproduction. Its prominent role in musical pleasure, thus, has exciting implications. Can music influence goal-directed reward processing? Can it do so beneficially, to faci litate learning and other reward-related functions? This thesis explores this potential with a musical manipulation of reinforcement learning. Participants chose pleasurable and neutral music from an experimenter-compiled database and then listened to this music during functional magnetic resonance imaging of a probabilistic selection task known to rely on striatal dopamine transmission. To distinguish the effects of musical pleasure on the learning and generalization of probabilistic stimulus-outcome relationships, 17 subjects listened to pleasurable music during a training phase and neutral music during a test, while 18 subjects listened to neutral music during training and pleasurable music during testing. Pleasurable music significantly enhanced reinforcement learning, as in a previous investigation, and activity in the left superior temporal gyrus, left orbitofrontal and ventromedial prefrontal cortices, right inferior frontal gyrus, and right insula was able to predict both musical pleasure and reinforcement learning task performance. There were also interactions between musical pleasure and neural responses consistent with a congruency effect, with pleasurable music enhancing attention for rewarding stimuli as reflected in the left occipital lobe, left middle frontal gyrus, left superior frontal gyrus, and right anterior cingulate cortex, although not in behavioral measures. Together, these findings support a role of dopamine in musical pleasure and suggest that this relationship can be exploited to aid both neural and behavioral functions of the reward system, with implications for education, decision making, and motivation.