| 英文摘要 |
Introduction: Physical activity (PA) has been shown to counteract the age-related decline of cognition, particularly the function of executive control. Specifically, evidence has attributed this benefit to the compensatory mechanism of brain due to chronical participation of PA. However, among various domains of executive function, interference control is a less studied, yet important, component in relation to PA in older adults. Therefore, the main purpose of current study is to investigate the effect of PA on the aspect of interference control of executive control function and the underlying neuroelectrical processes among healthy aging adults. Secondly, task difficulty was manipulated to test its effect on the relationship between executive function and PA. Methods: Fifty-one participants were recruited in this study, including 17 low PA older adults (LPAO), 17 high PA older adults (HPAO), and 17 younger adults (YA), who were served as a reference point of optimal or unimpaired executive control function. Interference control was measured using Stroop tasks (congruent v.s incongruent) with various task difficulties (3 v.s 4 colors) while event-related potentials (ERPs) were recorded. Results: The behavioral data shows shorter reaction time (RT) for HAPO and YA relative for LPAO in congruent condition, while shorter RT was observed for YA relative for two older groups in incongruent condition. The difference of Stroop effect between three groups was selectively observed in task with 4 colors, with larger Stroop effect for two older groups relative for YA and with larger Stroop effect for LPAO relative for HPAO. The results of P300 component revealed longer latency for LPAO relative for HPAO at Fz, Cz, and Pz electrodes and for YA at Pz. As for P300 amplitude, HPAO exhibited larger amplitude than LPAO and YA at Fz; YA exhibited larger amplitude than other two older groups at Cz, and HPAO exhibited larger amplitude than LPAO at Cz; YA and HPAO exhibited larger amplitude than LPAO at Pz. Conclusion: Current study provides evidence that higher PA in older adults is associated with faster reaction time, larger input of attentional resources, and faster information-processing rate during Stroop tasks requiring various extent of interference control. In addition, the association between higher PA and reduced Stroop effect in task requiring increased cognitive demand suggests that the benefit of PA on the aspect of interference control of executive function may be selective. Furthermore, the posterior-anterior shift of P300 amplitude in HPAO suggests a more developed compensatory mechanism which maintains a rather efficient function of executive control function. Collectively, these findings suggest that PA has significant influence on the function of executive control in aging population. |
