The Mechanism of Attentional Capture in the Impact of Physical Exercise on Response Inhibition in the Elderly: A Voxel-based Morphometry Study

Objective: To explore the mechanism of attentional capture in the impact of physical exercise on response inhibition in the elderly. Methods: The physical activity rating scale-3 and three-axis accelerometer ActiGraph GT3X+ were used to measure the physical activity levels of older adults by cross-sectional design, and then the older adults were divided into exercise group and control group according to the results. Participants in the two groups were finished three behavioral experiments, and the gray matter volume was detected by the structural magnetic resonance imaging. Results: 1) The stop signal reaction time(SSRT) of the exercise group was significantly shorter than that of the control group, and the SSRT was significantly correlated with the gray matter volume in the left supplementary motor area. 2) The attentional capture reaction time of the exercise group was significantly shorter than that of the control group, and both of the reaction time and accuracy were significantly correlated with the gray matter volume in the right inferior frontal gyrus. 3) The reaction time and accuracy of the exercise group were significantly better than that of the control group in the complex task, and the reaction time was significantly correlated with the gray matter volume in the left supplementary motor area, right inferior frontal gyrus, right superior frontal gyrus, the right middle frontal gyrus and the right rectus, the accuracy was significantly correlated with the gray matter volume in the right inferior frontal gyrus. Conclusions: 1) The physical exercise regulates the allocation of attentional resources and accelerates the capture of conflict signals are the possible mechanisms for the positive effect of physical exercise on the response inhibition in the elderly. 2) Physical exercise can increase the gray matter volume in the left precentral gyrus, left supplementary motor area, bilateral superior frontal gyrus, right middle frontal gyrus, right inferior frontal gyrus, right rectus, and right anterior/middle cingulate gyrus in the elderly. 3) The impact of physical exercise on the process of response inhibition in the elderly mainly involves the supplementary motor area, inferior frontal gyrus and middle frontal gyrus.The gray matter volume in the supplementary motor area is related to response inhibition, the gray matter volume in the inferior frontal gyrus is related to attentional capture, and the gray matter volume in the middle frontal gyrus is related to attentional resource allocation and working memory load of the task.