| Reaching or intercepting different objects is one of the most frequently activities in daily life.However,due to natural disasters,accidental injuries,various diseases and other factors,some people's motor sensory functions are damaged in varying degrees,which greatly affects the patients'daily life.For some patients with severe paralysis or missing limbs,research on motor function recovery based on implanted brain-machine interface(BMI)technology has been carried out internationally.By directly controlling external devices such as robotic arms or prostheses,the motor function of patients is reconstructed.At the same time,the analysis of motor sensory related neural information is one of the key factors to improve the ability to control the movement of external devices,although previous research on the analysis of motor sensory neural information has achieved many results.However,since most of the research is focused on the goal of the resting state,the prediction and tuning function of the brain area related to the motor sensory-related brain regions during the task of the movement guided by the goal of the exercise state is not clear,which makes it difficult Decoded neural signals are used to control the prosthesis/robotic arm in response to dynamic stimuli to produce predictive motion.Therefore,it is of great significance to explore the coding law of local field potential signals in the motor sensory area and the brain function connectivity between the motor sensory areas during the target-guided exercise process,which is of great significance to provide a theoretical basis for controlling the prosthesis/robotic arm to respond to dynamic stimuli.In this study,Rhesus are used as the research object,and a set of behavior training paradigms that guide the upper limbs of Rhesus to carry out stretching,grasping and intercepting movements in three-dimensional space by moving and stationary targets are designed and built.Multi-channel microelectrode arrays were implanted in the primary motor cortex,posterior parietal cortex and primary sensory cortex of Rhesus to record the neural signals in the target movement paradigm(TM)and target static paradigm(TS).Through analyzing the time domain frequency domain and peak frequency,the law of local field potential signals of the motor sensory brain area in the process of target-guided tasks in different states is analyzed.At the same time,the method of coherence analysis and Granger causality analysis is used to analyze the brain function connectivity law of the motor-motor sensory brain area during the task.The results showed that: 1)In the TM paradigm,the delta and theta have the lowest power when the target appears,and immediately increase with the appearance of the target object,and it reaches the maximum before the start of the movement,and then decrease in M1,S1,and PPC brain regions of the rhesus.The power variation of Beta frequency and Gamma1 frequency are opposite to that of Delta frequency and Theta frequency bands.It reaches the peak within 200 ms,and the power decreases at the late stage of the movement.In the TS paradigm,the Delta frequency and Theta frequency reach the highest value before and after the target appears,and reach the lowest value near the start of the movement;the peak value of the Beta frequency is within 200 ms before the target object.2)Compared with the TS paradigm,for the Beta frequency and the Gamma1 frequency,the peak time in the TM paradigm after the appearance of the target object is later than the TS paradigm,and the power is lower than the TS paradigm.At the same time,the local field potential power of the motor sensory brain area at the same frequency in the TM paradigm is higher.3)For the TM and TS paradigms,the functional connectivity between the M1 and S1 brain regions is the strongest.It also shows that the functional connectivity and causal connection strength between the motor sensory brain regions in the low frequency band(Delta frequency,Theta frequency and Beta frequency)are higher than that between motor sensory brain regions in the high frequency band(Gamma1 frequency and Gamma2 frequency).At the same time,the causal connection strength of the S1 brain region to the M1 brain region in different frequency bands is the highest,while the connection strength of the PPC brain region to the S1 brain region is the lowest.4)The functional connectivity between M1,S1,and PPC brain regions in the TS paradigm is higher than that in the TM paradigm;The causal connection strength of the S1 brain region to the PPC brain region in the TM paradigm is higher than that in the TS paradigm.Conclusions: 1)Beta oscillations induced in the motor-sensory brain area after stimulation by a moving target are higher than those induced by stationary targetstimulation brain areas.It is speculated that the Beta frequency has a tuning effect on targets of different motor states.When neurons produce more When the Beta frequency is high,the motion system will be ready to start moving quickly at the cost of pause.The local field potential at different frequencies has a tuning effect on the target's motion state.2)The M1 area accepts information input from the S1 area,and the integration of motor sensory functions is essential for exercise.PPC area may be helpful for detailed motor calibration and are closely related to motor intention and target-oriented movement planning.Its neurons can characterize high-level motion planning,and also play an important role in the feedback and feedforward loop of motion controlThis study can provide theoretical guidance for the control of prostheses under the brain-computer interface system in a dynamic environment,and is expected to provide guidance for the clinical application of implantable brain-computer interfaces.The relevant findings on the functional connection between the motor-sensory cortex have practical guidance for further understanding of the interaction between the cortex and the cortex,as well as the development of new treatment strategies for sensorimotor disorders. |
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