Differential impact of ageing on reward driven changes in motor control

Rewards can impact both the selection and execution of goal-directed actions. As individuals age, changes in reward processing may lead to reduced effects of rewards on motor control. This study examined how monetary rewards influence action execution and action selection during reaching movements, and whether these effects vary between younger and older adults.

A total of 28 younger adults and 28 older adults participated in the study. Non-distracted trials were employed to evaluate action execution, while trials containing distractions were used to assess action selection. Key outcomes included maximum velocity, movement time, endpoint error, reaction time, and selection accuracy.

The findings revealed that rewards boosted maximum velocity and shortened movement time in both age groups without increasing errors. These reward-induced changes in movement intensity were more pronounced in younger adults. When it came to action selection, rewards decreased reaction time but lowered selection accuracy, leading to faster but less accurate responses.

Notably, the effect of rewards on reaction time and selection accuracy did not differ significantly between age groups. The results suggest that ageing does not uniformly impair reward responsiveness. Instead, ageing tends to diminish the invigoration effect of rewards on movement, while the reward-related modifications in action-selection behavior remain consistent across different age groups.

These insights could prove valuable in the development of reward-based interventions aimed at enhancing movement vigor without encouraging excessive speed at the expense of accurate action selection.