Compensatory Mechanisms in Prefrontal and Reward Systems Reveal Delayed Brain Aging in Musicians

The reward system primarily releases dopamine in response to rewarding stimuli, including music. While compensatory interactions between the prefrontal and sensory cortices are essential in understanding cognitive aging in older musicians, the role of the reward system remains insufficiently understood. This study investigates whether the reward system supports compensatory mechanisms that mitigate age-related cognitive decline in older musicians. We recruited four groups-younger musicians, older musicians, younger controls, and older controls-and collected functional magnetic resonance imaging (fMRI) data during pleasant music listening. A cross-validated predictive model showed that the amplitude of low-frequency fluctuations robustly predicted years of musical training, indicating a strong association with musical expertise. Older musicians exhibited the same activation in the ventral caudate and primary sensory regions as younger musicians but demonstrated lower spontaneous activity in the prefrontal cortex. Controls showed distinct difference between old and young groups. Functional connectivity and behavior correlation analyses further revealed distinct prefrontal-reward system coupling in musicians versus controls. These findings suggest that long-term music training enables older musicians to maintain the activation of reward system to compensate for diminished prefrontal activation, thereby reducing cognitive load during music listening, indicating a potential compensatory mechanism that preserves cognitive function in aging musicians.