| In recent years, motor imaging therapy has been increasingly used in motor function rehabilitation for stroke patients in clinical practice. Studies have shown that motor execution(ME) and motor imagery(MI) activates the sensor motor system and uses the same neural mechanisms, and have confirmed that MI plays an important role in recovering movement dysfunction of stroke patients.With the development of modern science, functional brain imaging technology is increasingly used. Based on functional magnetic resonance imaging technology(f MRI), diffusion tensor imaging(DTI) and functional near Infrared Spectrum Instrument(f NISI) technologies, this study analyzes the neural mechanism underlying motor imagery in the treatment of stroke patients. The main contents and findings are as follows.â‘ Analyzing the basic principles of f MRI, DTI and NISI technologies, and studying the neural mechanism underlying motor imagery based on various imaging technologies. f MRI can investigate the brain cortex activation and information exchange between brain areas from the perspective of neuronal activity. DTI can visually display the fiber connection between brain areas, and monitor the brain microstructure changes. The use of NISI for studying the cortical activity can corroborate the results of f MRI and more accurately analyze the brain function under MI.â‘¡Based on the multi-modality imaging, analyzing the neuronal activity of brain functional areas of health subjects under MI and ME.1)The study has shown that the older group has stronger activation in the motor areas than the younger group, mainly in the premotor cortex(PMC), supplementary motor area(SMA) and primary motor cortex(M1). The activation of motor cortex during MI becomes more difficult with age increases; 2)The connection intensity during ME of right hand in the older group is greater than the younger group; 3)The valid connective network of elderly group is greater than younger group during MI, and there is significant difference in the valid connection in the contralateral brain regions; 4) The brain tissue structures of elderly people involving of movement and cognition and the structural loop connection intensity show a downward trend.â‘¢The combined use of f MRI and DTI to study the neurophysiological mechanisms of brain motor dysfunction in stroke patients. 1) During ME of right hemiplegia hand, the contralateral SMA, PMC and M1 are significantly activated, the ipsilateral motor regions area is less activated, and the laterality is obvious. During MI of right hemiplegia hand, the bilateral M1, SMA, PMC are strongly activated, but the lateralization is reduced. 2) The motor cortex and non- motor areas are obviously activated during ME of left hemiplegia patients; during MI, the motor areas are less activated and the non- motor areas are obviously activated. Similar results are found in the function network of motor cortex in stroke patients. 1) During ME of the affected hand, there is information loop and less valid connection between each hemisphere brain region. 2) Compared to the control group, the valid connective network during ME and MI of the hemiplegic patients is simple, the valid connection strength is weak, which is more serious during MI. 3) The structure connection is significantly reduced between motor cortex, motor cortex and subcutaneous nuclei. These results suggest that if the affected hand is dominant, the brain function activation of MI and ME is similar to that of health subjects; if the affected hand is non-dominant, the activation of non- motor areas is related with function remodeling of stroke patients. This result partly explains the reason that stroke patients have motor dysfunction. Because of brain lesions, the sports-related brain tissue structure is significantly decreased in stroke patients, the activation of brain sports area is difficult, the information exchange is little between function areas, thus resulting in movement dysfunction. Despite of abnormalities in motion control, exercise programs, motor areas, functional network and structure network, MI can provide an effective way to stimulate the activation of mo tor cortex in stroke patients, activate the original movement loop and promote the rehabilitation of motor function.â‘£ Clinical application of motor imagery therapy. This study designs the motor imagery therapy consistent with daily rehabilitation for stroke patients, longitudinally tracks 2 stroke cases of conventional rehabilitation and 6 cases of rehabilitation and MI therapy, collects f MRI data before treatment and 4 weeks after treatment, and simplifies motor function assessment of FMA. After a period of MI training for stroke patients, it is found that MI can more easily activate motor function areas, the brain activation pattern is notably better than early activation, the activation intensity and the activated voxels are closer to healthy subjects, and the functional rehabilitation speed is significantly better than that of conventional therapy patients. The study confirms that MI therapy in combined with conventional rehabilitation can strengthen the initiative motor learning, promote functional recovery of limb movement, and provide a theoretical basis for motor imagery therapy in clinical practice.This study uses a variety of imaging techniques, explores the neural mechanisms of brain function of healthy subjects from aspects of brain functional orientation, brain function network and brain structure network. In addition, based on the findings on healthy subjects, the authors further study the motion system functional brain imaging of stroke patients. Finally, according to the findings of imaging, the authors design MI therapy for stroke patients and conduct it in clinical study. This study provides imaging evidence for MI therapy, and also provides objective indicators for observing the effectiveness and indications of MI therapy, which plays an important theoretical and practical value for the clinical treatment of stroke rehabilitation. |
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