| 其他摘要 | Exercise and cognitive training are effective approaches to delay cognitive decline in older adults. The effects of combined exercise and cognitive training on cognition in older adults have received growing attention in recent years. The "adaptive capacity model" suggests that a hunter-gatherer lifestyle of ancestors required the coordination of the body and brain, and the frontal lobe plays a critical role in dealing with the dual task. With aging, the structure and function of the frontal lobe decline significantly, and the frontal一dependent cognitive function will be seriously damaged due to the aging of the frontal lobe. Therefore, from the perspective of evolutionary neuroscience, it is necessary to carry out exercise and cognitive training simultaneously to combat the decline of frontal lobe functions with aging. Currently, a few studies have examined the effects of combined exercise and cognitive training on frontal lobe functions in older adults, however, inconsistent results are reported. First, most of the studies reported negative effects mainly adopted the sequential combined training model (exercise and cognitive training are carried out separately), which directly contradicted the theory of "adaptive capacity model". As for the simultaneous combined training researches, the exergame training is usually lacking of difficulty and intensity to induce the change of frontal lobe functions. Dual-task training ensures the difficulty and intensity somehow, but none of the existing studies directly compare the behavioral and neural effects of combined training with single training.
In this study, the simultaneous combined training of aerobic cycling and video games was carried out under the condition of maintaining moderate intensity exercise level and cognitive complexity. The recruited healthy elderly living in the community were divided into aerobic exercise group (n=22), video game group (n=23), combined training group (n=22) and control group (n=21).All participants in the training group received 32 sessions of 60 minutes twice a week for 4 months, while the control group kept their lifestyle the same. In this study, the effects of combined training on enhancing frontal lobe functions, especially when compared with single training approach, were comprehensively investigated from the behavioral and neural basis by analyzing the neuropsychological and magnetic resonance data at pre- and post-test.
Study 1 investigated the effects of combined training on frontal-dependent cognitive function in older adults. The results showed that frontal-dependent cognitive function was only significantly increased in the combined training group (p=0.03). It remained unchanged in the aerobic training group and video game training group (all p<0.05), whereas significantly decreased in the control group (p=0.01). Study 2 investigated the effect of combined training on the plasticity of frontal lobe structure in older adults. The results showed that combined training had limited effect on increasing the thickness of the frontal gray matter cortex (all p<0.05). However, as for white matter, a significant group-by-time interaction was found on mean diffusion of the right corticospinal tract after rigorous adjustment for multiple comparisons (p=0.001).The post-hoc test indicated that the mean diffusion was significantly decreased in the combined training group p=0.002). Similarly, for axial diffusion, a group x time interaction was also found on the right corticospinal tract p=0.001)，manifested as significant increased axial diffusion in the single aerobic exercise group and single video game group (all p<0.05). In addition, at the individual level, the current study also found that the decrease of axial diffusion of sagittal stratum in the combined training group and aerobic exercise group was significantly correlated with the improvement of frontal-dependent cognitive function. Study 3 investigated the effect of combined training on the functional connectivity of core brain network that associated with frontal lobe. The results suggested that only combined training significantly improved functional connectivity between bilateral frontal-parietal networks切=0.039). However, at the individual level, the change of frontal-parietal network functional connectivity was not significantly with the change of frontal-dependent cognitive function.
The results collectively show that only the combined training of aerobic exercise and video game can significantly improve the frontal lobe functions in older adults, and the combined training effect is mainly reflected on the changes of white matter integrity and frontal-parietal network functional connectivity. In the future, simultaneous combined training targeting at the frontal lobe may be an effective way to enhance the plasticity of the frontal lobe, improve the frontal-dependent cognitive function in older adults, and even delay the progression of dementia. |
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