Distinct roles of brain network flexibility in motor learning across age

Motor learning is a lifelong process, from infancy through old age. Acquiring new motor actions through repetitive practice requires adjusting motor output in response to sensory input and integrating them to facilitate learning. For this to occur, the central nervous system must flexibly predict and adapt to the dynamic interplay between sensory inputs and motor outputs. Although overall brain function changes with age, it remains unclear how the flexible brain network evolves and influences motor learning ability with aging. To address these open questions, we designed a visuomotor learning task involving both younger and older adults and quantitatively assessed brain network flexibility, leveraging multichannel electroencephalography (EEG) in humans. Here, we found age-group differences in motor learning properties, brain network flexibility, and their neural relationships. In younger adults, learning aftereffects were associated with brain network flexibility during the preparatory period of the task. However, this association was not observed in older adults. Together, our findings suggest that brain network flexibility during the preparatory period, rather than motor execution, was critical for acquiring and maintaining new motor actions in younger adults, but that this coupling was attenuated with aging.