| With the acceleration of the aging in China,the tissue degradation caused by aging is often accompanied by the decline of cognitive function.The biggest deficiency is executive function(EF),which is particularly important for maintaining the daily life and independent activities of the elderly.The decline of EF can lead to a variety of neuropsychiatric diseases,such as mild cognitive impairment,Alzheimer's disease,etc.,which will cause a huge burden on both family and society.Therefore,delaying the decline of EF is urgent in response to the aging.Physical activity(PA)has been found to be a relatively easy,highly implementable,cost-effective,non-pharmacological intervention that can provide neuroprotection during aging,thereby making it possible to improve cognitive function.A large number of studies have shown that PA has a positive effect on EF,and EF seems to benefit the most from PA.However,the effect of PA on EF decline in the elderly has not yet been concluded,and there are few studies on the relationship between PA and EF decline and related brain processing characteristics among individuals with different PA levels.Therefore,this study used high spatial resolution functional magnetic resonance imaging(f MRI)to explore the relationship between PA and EF and the characteristics of brain activation among healthy elderly.Study 1(Experiments 1,2,and 3)recruited the healthy elderly(the elderly group)as the main participants,and the healthy young(the young group)as the control group.International Physical Activity Questionnaire Short Form,the Chinese version of the Montreal Cognitive Assessment-Basic,the Repeatable Battery for the Assessment of Neuropsychological Status,and three tasks(Flanker task,N-back task,Switching task)were used to explore the decline of EF(inhibitory control,working memory,and cognitive flexibility)in the elderly and its relationship with PA.Study 2(Experiment 4)used f MRI technology to investigate the characteristics of brain activation in the elderly with the decline of EF.Study 3(Experiment 5)also applied f MRI technology to distinguish and compare differences of brain activation in the elderly group with different PA levels,in order to further explore the relationship between brain function changes and PA,and provide evidence for the effect of PA on EF and brain function decline in the elderly.The results showed that:(1)Study 1: a)The inhibitory control of the elderly group was significantly lower than that of the young group,and the inhibitory control component of EF also declined.The inhibitory control of the elderly group with high PA level was significantly higher than that of the elderly group with low and medium PA level.b)The working memory of the elderly group was significantly lower than that of the young group,and there was a decline in working memory.There was no significant difference in working memory between different PA levels in the elderly group.c)The cognitive flexibility of the elderly group was significantly lower than that of the young group,indicated that the decline of cognitive flexibility.The cognitive flexibility of the elderly group with high PA level was significantly lower than that of the elderly group with low and medium PA level.(2)Study 2: a)Compared with the young group,the elderly group activated a wider range of brain regions when completing the EF process.The activated brain regions of inhibitory control were mainly in the prefrontal lobe(BA 10,BA 11,BA 46)and showed unilateral activation on the right side.The activated brain regions of working memory was mainly in prefrontal and subcortical regions(BA 10,BA 23,BA 45).With the increase of working memory load,more brain regions were activated,i.e.,from unilateral(left)to bilateral activation.Cognitive flexibility related brain regions were mainly in the frontotemporal lobe and cerebellum(BA 6,BA 38,BA 45,BA 48).b)In the elderly group,there were significant correlations between inhibitory control and right middle frontal gyrus(BA 46),working memory and right middle frontal gyrus(BA 45),and cognitive flexibility and activation levels of cerebellum,left orbital inferior frontal gyrus(BA 45),left putamen(BA 48),and right inferior frontal gyrus(BA 45).(3)Study 3: a)Compared with those with high PA level,the elderly with low and medium PA levels activated more brain regions to complete the task.Specifically,inhibitory control was mainly concentrated in the prefrontal lobe(BA 10,BA 39).Working memory was mainly in the frontal and subcortical regions(BA 6,BA 24,and BA 48).Cognitive flexibility was mainly concentrated in areas such as the prefrontal cortex(BA 11,BA 17,BA 19,BA 32,BA 46).b)In the elderly group,the working memory was significantly correlated with the activation levels of the left middle frontal gyrus(BA 46,BA 48),and the cognitive flexibility was significantly correlated with the activation levels of the right superior frontal gyrus(BA 32),the right anterior cingulate and the paracingulate gyrus(BA 32).The conclusions of this study are as follows:(1)Decline in EF(inhibitory control,working memory,and cognitive flexibility)was found in old adults.The levels of PA among healthy elderly were correlated with inhibitory control and cognitive flexibility of EF.(2)The decline of EF in the elderly was associated with changes in the function of a wide range of brain regions,which were mainly in the frontal and prefrontal lobes.(3)PA level can improve this inefficient brain activation pattern in the elderly,and the activated brain regions were significantly related to PA level were mainly located in the prefrontal lobe. |
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