Age-related shift towards feedforward motor control under uncertainty

Humans perform movements in the face of uncertainty on a daily basis. To accomplish these tasks without error, young adults frequently rely on feedback-mediated motor strategies that allow them to update their movement as uncertainty evolves. However, it remains unclear how aging impacts the ability to plan and execute movement under uncertain conditions. Here we use a “go-before-you-know” pointing task completed during functional neuroimaging to examine how aging influences movement planning under uncertainty. Behaviorally, young adults employed a strategy consistent with feedback-mediated control, biasing their trajectories toward the more likely target when uncertainty was low, and intermediate to potential targets when uncertainty was high. Older adults employed a different approach, shifting away from an intermediate reaching strategy, particularly under high uncertainty, suggesting a shift toward feedforward control. Neuroimaging mirrored these behavioral patterns, revealing that young adults encoded task uncertainty and movement direction in sensorimotor regions more strongly than older adults. Overall, these findings suggest that aging diminishes the ability to flexibly encode task-related uncertainty, leading to a shift towards feedforward control strategies.