Effects Of Sensory Disturbance And Control Mechanism Of Uprignt Stance Stability

Multi-sensory integration and postural control refer to posture control system(PCS),which integrates redundant information from the same or different posture sensory channels into a unified,effective and stable internal posture representation and couples posture control mechanism to realize information processing and system control activities of stability.It is an important physiological function of human adaptation to environment,life,work and learning.The important characteristics of brain information processing have important significance and application value in the fields of Engineering psychology,human factor engineering,clinical medicine,sports science and even intelligent robot control.It is recognized as one of the important contents of contemporary brain and neuroscience research.PCS is a structural and functional system for realizing multi-sensory integration and posture control.It consists of three basic functional modules:multi-sensory afferent,multi-sensory integration of brain,multi-muscles and multi-mechanism.Visual provides information of body relative spatial position and body motion state,and position afferent provides head space position and body straight line and rotation speed.Proprioceptive afferents provide information about the spatial position of limbs,the position relationship between limbs and the state of motion,and plantar tactile afferents provide external reference stability information.Brain multi-sensory integration mechanism dynamically constructs the internal table of body posture through multi?sensory interaction and reweighting according to the reliability of the afferent information of different sensory pathways.The central multi-muscles group and multi-mechanism through feedforward control,feedback control and random control form the anticipatory posture adjustment,compensatory posture adjustment and random posture adjustment,according to different environmental conditions,using different strategies,start and coordinate postural muscle and motor muscle activities,then effectively cope with the negative effects of various internal and external disturbances on body gravity center stability and limb spatial positioning,and achieve multi-muscle group and multi-mechanism coordinated control of upright stance stability.Previous studies using the "sensory blockade and sensory disturbancee paradigm have shown that the stability reflected by the sole pressure center(COP)and the body center of mass(COM)under static standing conditions has obvious multi-sensory input compliance in standing posture.When standing on the stable support,about 70%of information is from the proprioceptor,20%from the vestibular sensor and 10%from the visual sensor;while when the unstable support interface is standing,PCS will adjust the sensory weight and rely more on the vestibular position sensor and the visual sensor to obtain posture information.However,under these conditions,it is not entirely clear how PCS can start the multi-muscle group posture control mechanism to maintain the posture stability based on the internal posture representation formed by multi-sensory input and multi-sensory integration.In this study,based on the "multi-sensory integration model" of posture stability and the "anticipation and compensation posture regulation theory",the effects of visual,proprioceptive and plantar tactile inputs on stability,muscle activity and posture comtrol were observed by changing the reliability of the inputs without changing the input of position information,and the stability,muscle activity and posture regulation were discussed in depth.This paper focuses on the scientific issues of the effects of visual,proprioceptive and plantar tactile disturbances on static stability,muscle activity and posture regulation,and forms six series of experiments in three parts.Results show that the uncertainties of sensory information and the difficulty of standing posture caused by visual,tactile and proprioceptive disturbances can significantly destroy the stability.In this process,the posture control system can cope with the influence of postural sensory disturbance and difficulty of standing posture on the stability of standing posture by activating part of the postural muscles in advance and enhancing the intensity of pre-activation.That is to say,"Hip Posture Muscle Group Control Strategy" is the main response to sensory disturbance,while "Lower Limb Posture Muscle Group Control Strategy" is the main response to the difficulty of standing posture.