Assessing age-related changes in brain activity during isometric upper and lower limb force control tasks

Area of Science:

• Neuroscience
• Motor Control
• Aging Research

Background:

• Aging effects on neural control of upper and lower limbs are not fully understood.
• Functional MRI studies often focus on hand movements, neglecting lower limb complexities.
• Older adults (OA) are frequently used as controls, but their distinct neural patterns require investigation.

Purpose of the Study:

• To investigate age-related differences in the neural control of both upper and lower limb movements.
• To compare brain activation patterns during motor tasks between healthy young adults (YA) and OA.
• To understand if OA recruit additional neural resources to maintain motor performance.

Main Methods:

• Functional MRI was used to examine brain activity in 16 YA and 20 OA.
• Participants performed pinch grip (upper limb) and ankle dorsiflexion (lower limb) tasks at 15% maximum voluntary contraction.
• Force control dynamics, variability, and accuracy were assessed alongside neural activation.

Main Results:

• Both YA and OA achieved similar force targets with comparable variability and accuracy.
• OA showed altered force control dynamics: slower force increase (hand) and faster decrease (foot).
• OA exhibited more widespread brain activation, including premotor, visuo-motor, and cerebellar regions, compared to YA.

Conclusions:

• Older adults may recruit additional brain areas, particularly cerebellar regions, to achieve motor task performance similar to younger adults.
• These findings suggest a compensatory neural strategy in aging.
• Further longitudinal studies are needed to track changes in motor performance and brain activation over time.