“These findings underscore an age-related shift in the neural dynamics underpinning motor adaptability with aging, pointing to increased BOLD variability modulation as a potential marker of compensatory reorganization in late adulthood.”
Coordinating both hands is something most people take for granted. Everyday activities such as buttoning a shirt, preparing a meal, driving, or using a knife and fork all depend on the brain’s ability to precisely control movements on both sides of the body. As people age, however, these tasks often become more difficult, especially when they require both hands to perform different movements at the same time.
A research paper published in Volume 18 of Aging titled “Age-specific relationship between the modulation of brain dynamics in response to task demands and bimanual performance,” investigated how aging affects the brain’s ability to adapt to increasingly complex hand-coordination tasks. The study was led by first author Sara Magalhães Ferreira from Hasselt University, with corresponding author Koen Cuypers from Hasselt University and KU Leuven.
Looking Beyond Brain Activation
For many years, scientists studying healthy aging have focused primarily on which brain regions become more or less active during movement. However, brain activity is not static. Even while performing the same task, activity naturally fluctuates from moment to moment.
These fluctuations, known as Blood Oxygen Level-Dependent (BOLD) variability, may provide important information about how flexibly the brain adapts to changing demands. Rather than measuring average brain activity alone, BOLD variability reflects the dynamic changes in neural activity over time and has emerged as a potential indicator of neural adaptability and efficiency.
Although previous studies have linked BOLD variability to cognitive aging, its role in complex motor functions such as coordinating both hands had remained largely unexplored.
Testing How the Aging Brain Responds to Increasing Motor Demands
To investigate this question, the researchers recruited 22 younger adults and 23 older adults, who performed a series of increasingly challenging bimanual tracking tasks while undergoing functional magnetic resonance imaging (fMRI).
The tasks required participants to coordinate both hands under three levels of difficulty. While some tasks involved moving both hands together in relatively simple patterns, others required different movement speeds and timing between the hands, placing greater demands on motor control and executive function.
As expected, older adults performed less accurately than younger adults, particularly during the most complex coordination task.
The Brain Responded Differently With Age
Rather than simply comparing overall brain activity, the researchers examined how BOLD variability changed as task difficulty increased.
Older adults showed greater BOLD variability in a cerebellar region and greater modulation of BOLD variability across several sensorimotor and cerebellar regions as task demands increased. These findings suggest that the aging brain adjusts its neural activity differently when faced with more challenging movements.
Importantly, these findings suggest that the changes reflected different strategies for adapting to increasing motor demands rather than simply indicating reduced brain function.
Different Brain Strategies Predicted Better Performance
One of the study’s most interesting findings was that the relationship between brain dynamics and motor performance differed between younger and older adults.
Among younger adults, smaller changes in BOLD variability within several sensorimotor and visuospatial brain regions were associated with better task performance. This suggests that younger brains may already operate efficiently and require relatively little adjustment as task difficulty increases.
In contrast, older adults who showed greater modulation of BOLD variability in regions of the parietal cortex generally performed better on the coordination tasks. These brain areas help integrate sensory information, guide movement, and support attention during complex motor activities.
Across both age groups, greater modulation in the middle occipital gyrus—a region involved in visual processing—was associated with better performance, whereas greater modulation in the cerebellar Crus I was linked to poorer performance. These findings suggest that the contribution of individual brain regions to successful movement changes with age.
How the Aging Brain May Adapt
Although the study was not designed to determine the precise biological mechanisms behind these findings, the results support the idea that the aging brain can reorganize its activity to compensate for age-related changes.
Rather than relying on the same neural strategies used by younger adults, older individuals may recruit additional brain networks and dynamically adjust neural activity as task demands increase. This flexible reorganization may help preserve motor function despite the structural and physiological changes that naturally occur with aging.
The findings are consistent with theories suggesting that healthy aging involves both gradual neural decline and compensatory adaptations that help maintain everyday function.
What Makes This Study Different?
Most previous neuroimaging studies of aging have focused on average brain activation. In contrast, this study examined how fluctuations in brain activity change as movement tasks become more demanding.
It is also among the first studies to investigate BOLD variability during complex bimanual coordination rather than cognitive tasks alone. By combining advanced functional MRI analyses with increasingly difficult motor challenges, the researchers were able to identify age-specific patterns of neural adaptability that traditional measures of brain activation may overlook.
Looking Ahead
The authors conclude that aging is associated with important changes in how the brain dynamically responds to increasing motor demands. Rather than reflecting simple decline, greater modulation of brain activity in certain regions may represent a compensatory strategy that helps older adults maintain coordinated movement.
Although larger studies will be needed to confirm these findings, the results suggest that measuring BOLD variability may provide new insights into healthy brain aging and motor adaptability. As researchers continue to investigate the neural mechanisms underlying movement, these findings may help guide future strategies aimed at preserving coordination, independence, and quality of life throughout aging.
Click here to read the full research paper published in Aging.
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