Systems Neuroplasticity in the Aging Brain: Recruiting Additional Neural Resources for Successful Motor Performance in Elderly Persons

TLDR

Seniors exhibit more elaborate brain activation during motor tasks, raising questions about whether this overactivation reflects compensatory recruitment or dedifferentiation. We investigated whether age‑related overactivation reflects compensation or dedifferentiation mechanisms. We correlated performance on a complex interlimb coordination task with brain activation. Elderly participants showed activation of classical motor coordination areas plus higher‑level sensorimotor and frontal regions, and higher activation in these regions positively correlated with motor performance, supporting compensation as the underlying mechanism.

Abstract

Functional imaging studies have shown that seniors exhibit more elaborate brain activation than younger controls while performing motor tasks. Here, we investigated whether this age-related overactivation reflects compensation or dedifferentiation mechanisms. “Compensation” refers to additional activation that counteracts age-related decline of brain function and supports successful performance, whereas “dedifferentiation” reflects age-related difficulties in recruiting specialized neural mechanisms and is not relevant to task performance. To test these predictions, performance on a complex interlimb coordination task was correlated with brain activation. Findings revealed that coordination resulted in activation of classical motor coordination regions, but also higher-level sensorimotor regions, and frontal regions in the elderly. Interestingly, a positive correlation between activation level in these latter regions and motor performance was observed in the elderly. This performance enhancing additional recruitment is consistent with the compensation hypothesis and characterizes neuroplasticity at the systems level in the aging brain.