Based On Multivariate Granger Causality Analysis Of The Mechanism Of Acupuncture Therapy For Stroke Hemiplegia

Stroke is a disease characterized by high prevalence, high mortality, high morbidity and high recurrence rate. About75%of the survivals suffer from different degrees of neurologic dysfunction of which hemiplegia is a common problem. Hemiplegia creates a huge burden to both family and community, seriously impacting the quality of the patient’s daily life and social participation. Seeking effective therapies that help to improve motor function and speed recovery remains an important issue.As one of the important parts of Chinese medicine,acupuncture has been used extensively in the rehabilitative treatment of hemiplegia in China,and its effect of treatment has been proved in many clinical observation studies.1.Study of motor network during resting state,passive movement task and acupuncture at GB34in healthy subjectsObjective:To investigate the activity of motor network and possible changes modulated by acupuncture at BG34in healthy subjects by exploring the multivariate Granger effective connectivity patterns during resting state, passive movement task and poststimulus state of acupuncture at GB34.Methods:The functional MRI study was performed in8healthy subjects during resting state, passive movement task of affected hand and acupuncture at GB34. Multivariate Granger Causality Analysis was used to analyze effective connectivity patterns of resting state, passive movement task and poststimulus state of acupuncture at GB34. Results:The right postcentral gyrus emerged as the hub of motor network during passive movement task of left hand.Information from left precentral gyrus, precuneus, inferior parietal lobule, insula, lateral nucleus of thalamus and middle temporal gyrus flowed to this brain region. Precuneus emerged as the hub of the network during resting state, receiving information from insula, anterior cingulate cortex, posterior thalamus and Middle temporal gyrus and sending information to substantia nigra and superior temporal gyrus.Left precentral gyrus and postcentral gyrus, inferior parietal lobule emerged as the hub of network during poststimulus state of acupuncture at GB34. Effective connectivities from several brain regions including declive, posterior thalamus, midcingulate cortex, substantia nigra and inferior parietal lobule to bilateral precentral gyrus and postcentral gyrus were increased in comparison to motor network in the resting state. Connectivities of precuneus with other brain region were decreased.Conclusion:Combining an experimental paradigm using non-repeated event-related design and multivariate Granger causality analysis in fMRI study of acupuncture effect was consistant with time-varied characteristics of acupuncture effects.Effective connectivities between somatosensory cortex and motor related subcortical brain regions emerged during motor task. Acupuncture at GB34increased effective connectivities from cerebellum, thalamus, cingulate cortex and inferior parietal lobule to bilateral precentral gyrus and postcentral gyrus,which may contributed to the recovery of motor function and analgesia.2. Study of motor network during resting state,passive movement task and acupuncture at GB34in hemiplegic patients and comparison of motor ne twork between healthy subjects and hemiplegic patientsObjective:To investigate the mechanism of motor impairment after stroke by comparing the motor network between hemiplegic patients and healthy subjects during motor task. To investigate the mechanism of acupuncture promoting motor recovery by comparing the motor network changes modulated by acupuncture at GB34between hemiplegic patients and healthy subjects during poststimulus state of acupuncture at GB34.Methods:The functional MRI study was performed in9hemiplegic patients during resting state,passive movement task of affected hand and acupuncture at GB34.Multivariate Granger Causality Analysis was used to analyze effective connectivity patterns of resting state,passive movement task and poststimulus state of acupuncture at GB34.Results:Connectivities of motor related cortex and subcortical brain regions decreased during motor task in hemiplegic patients compared with healthy subjects.Left precentral and the postcentral gyri, insula, lateral nucleus of thalamus,culmen emaerged as the hubs of the network during poststimulus state of acupuncture at GB34in hemiplegic patients. Acupuncture at GB34increased mutual effective connectivities between culmen and bilateral precentral and the postcentral gyri in comparison to resting state in hemiplegic patients. Conclus ions:Decreased effective connectivities between sensorimotor cortex and cerebellum,basal ganglia and limbic system leaded to dysfunction of motor integration and consequently motor impairment.Acupuncture increased mutural information flows between sensorimotor cortex and cerebellum,which consequently promoted motor integration and improvde motor function.The target sites of acupuncture at GB34in central nervous system are more concentrated on cerebellum and more disease in hemiplegic patients in comparison to healthy subjects.