Accumulated reserves hold back age-related neural compensation in speech-in-noise perception

During cognitive tasks, increased frontoparietal neural activity and functional connectivity are commonly observed in older adults. Cognitive reserves accrued from positive life choices can provide additional neural resources to cope with aging. However, how cognitive reserves interact with upregulated neural activity in older adults is poorly understood. We measured brain activity with fMRI during a speech-in-noise task and assessed whether cognitive reserve accumulated from long-term musical training bolsters or holds back age-related upregulated activity. Older musicians exhibited less upregulation of task-induced functional connectivity than older non-musicians in auditory dorsal regions, which predicted better behavioral performance in older musicians. These results suggest that cognitive reserve may hold back neural recruitment. Besides functional connectivity strength, we also found that older musicians showed more youth-like fine spatial patterns of functional connectivity than older non-musicians. Our findings enlightened the intricate interplay between cognitive reserve and age-related upregulated activity during speech in noise perception. Significance StatementUnderstanding the interplay between cognitive reserve and age-related neural changes is vital for developing strategies to mitigate cognitive decline in older adults. This study reveals that long-term musical training, which provides cognitive reserve for speech perception, helps older musicians preserve youth-like levels of functional connectivity and fine-scale activity patterns in the auditory dorsal stream during speech-in-noise perception. Unlike older non-musicians, who exhibit age-related neural upregulation, older musicians maintain youth-like connectivity patterns akin to those of younger adults, resulting in superior speech-in-noise perception. These findings support the "Hold-back upregulation" hypothesis and suggest that musical training counteracts age-related declines by preserving youthful brain function. The results offer valuable insights for designing interventions to enhance aging populations cognitive function and communication abilities.