Effect Of Physical Activity On The Executive Function Of Postmenopausal Women And The Related Mechanisms

Executive function is the highest level cognitive activity of the cerebral cortex to control and regulate all cognitive processes, which is demonstrated by the execution control ability of individuals to initiate and complete an aimed activity. Decline of executive function comes earlier than the decline of general recognition ability and has a greater outcome, and it can progress to recognition disorders if not timely treated, which has severe influence on the life quality of the elderly. With the social aging problem has become increasingly serious, the World Health Organization predicts that by 2020, there will be 29 million people worldwide with dementia, of which two-thirds of patients with AD. Especially for the postmenopausal women, the group with the morbidity of AD was 2-3 times higher than men in the same age. Therefore, how to effectively slow down cognitive decline in postmenopausal women is an important issue in today’s gerontology research areas. Studies have proven that physical activity may promote the formation of new neural circuit in certain brain areas(for example the hippocampus) and effectively compensate for the damages come along with aging, which subsequently delays the executive function. Previous studies have drawn different conclusions concerning the levels of physical activities; whether physical activity can improve all the three aspects of execution function(inhibition, updating, and switching) and the influencing characteristics and mechanisms of brain processing all needed further study.Therefore, the present research, taking the theories of recognition aging, execution control, and information processing as the background, physical activity and execution process as the main procedure, studied a total of 40 healthy postmenopausal women from 20 communities in urban Shanghai. The execution behavior and the execution processing were studied in postmenopausal women undergoing different levels of physical activity using Go-Nogo, N-back, and More-odd Switching tests, so as to understand the characteristics and the neurophysiology mechanism by which physical activity influence their execution function(inhibition control, memory updating, and attention switching), further contributing to the theory of cognition aging and execution control and providing evidence that physical activity can delay the decline of execution function in the elderlyOur results revealed that:(1) In the inhibition control mission, the two groups both had higher Nogo inhibition rate, and the highly active group had a markedly rapid Go reaction than the medium active group; in the conflict surveillance period the highly active group had apparent Go-Nogo effect during the latency of N2 in parietal region, and had greater Go-N2 amplitude and Nogo-N2 amplitude were elicited in central-parietal region than the medium active group. Meanwhile, in the inhibition processing period, the highly active group had markedly shorter Nogo-p3 latency compared with the medium active group, and the Nogo-P2 peak had apparent Go-Nogo effect; the P3 in parietal region was much greater, with short latency.(2) In the memory refreshing mission, the highly active group had quicker reaction and more accurate behavior under both high and low load missions compared with the medium active group. For figure information coding, matching, refreshing, and transient storing, the P3 amplitudes of both groups were decreased with the increase of memory load. The medium active group was sensitive to recognition load, indicating that 3-back-P3 latency was markedly longer than 1-back. However, the highly active group received less influence from the memory load and had a stronger mobilization, allocation and utilization of the recognition resources, meaning that the amplitudes of 1-back, 3-back and D-N450 amplitudes were all greater than those of the medium active group in the frontal- central-parietal region.(3) In the attention switching mission, the highly active group had better accuracy of switching and non-switching behaviors, reaction speed and global cost compared with the medium active group. The two groups were both influenced by mission load that meanswitch-P3 amplitudes elicited in central-parietal-occipital region. In the non-switch mission, the non-switch-p3 latency of the highly active group was longer than switch-p3 and the non-switch-p3 of the medium active group. When the mission was intensified(from repeat to change), the highly active group had better recognition processing strategy, and mission change could be accomplished with less recognition resources; however, for the medium active group, even with more resources(increased P3 amplitude in parietal region), the accuracy and reaction time were still limited.Analysis of the findings of our three experiments yielded the following conclusion:(1) physical activity can effectively improve the adaption to complicated environment in the postmenopausal women, as manifested by rapid reaction to interfering information, optimized strategy of recognition resources, and efficient inhibition processing, etc.(2) Physical activity can effectively promote the work memory load of the postmenopausal women, as manifested by improved adaption to different memory loads, flexible processing of coding, matching, and transient storing of memories, and efficient allocation of recognition resources.(3) Physical activity can effectively improve the attention transform and coordination of the postmenopausal women, which is demonstrated by improved coordination of working memory and inhibition function during multiple job switching and the flexible transfer according to different principles.(4) Physical activity can effectively promote the execution function of the postmenopausal women, and highly active physical activity can contribute to rapid and accurate reaction, rapid and better activation of frontal- central-parietal region, and subsequently promote their execution function.The present study contributes to the research that active physical activity can effectively delay the decline of execution function in the postmenopausal women, providing neurophysiology evidence that physical activity can protect execution function in postmenopausal women and contributing to the theory of physical activity, recognition aging, and execution control. Meanwhile, the present study proved from the behavior and psychological aspects that physical activity can improve the execution function(inhibition control, memory updating, and attention switching) in postmenopausal women under different physical activities. The postmenopausal women with highly active activity have more rapid and accurate inhibition-updating-switching ability in execution behavior, which is due to that the physical activity promoted reaction and processing of frontal- central-parietal region in interfering environment in postmenopausal women, optimized the processing strategy and the inhibition-updating-switching coordination. Secondly, this study, by combining ERP technique and execution control-associated psychological mission, studied the three important components of execution function and provided objective evidence for explanation of the previous controversy in the area, a basis for intervention of recognition aging in the future, and evidence for the feasibility and effectiveness of physical activity as intervention for recognition aging.