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Preliminary Study of Corticomuscular Coordination Mechanism Related to Force Output

Author: ZhangYang
Tutor: HouWenSheng
School: Chongqing University
Course: Biomedical Engineering
Keywords: Magnetoencephalography Finger strength Neuromuscular coordination Event-related power spectrum Coherence analysis
CLC: R318.0
Type: Master's thesis
Year: 2011
Downloads: 40
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Abstract

Motion control of the function of the realization of human finger movement and brain systems have a close relationship, projected from the hand to the motor cortex, the area shows that the control mechanism of the brain to finger movement is very complex. Currently, the study of neural regulation mechanism of the manpower to expand mainly from cortical neural activity, EMGs and muscle strength. Voluntary contraction movement in addition to different sports related is a nexus between the cortex, the electrical signals generated by the neural activity of the primary motor cortex and muscle surface is associated, this correlation reflects the cerebral cortex activity between control muscle contraction functional linkages. Therefore, the the brain magnetic signal (Magnetoencephalography, MEG) and surface EMG (surface Electromyography, sEMG) combining and coordinating role between the cortical neural activity and muscle activity, and cortical muscle coherence quantitative estimates finger motor function control and adjustment mechanism is of great significance for the study of the central nervous system. Discussed neuromuscular adjustment mechanism based on MEG finger strength from the following aspects: First, design a different finger movement patterns, including simple rhythmic button task the different force tracking task, which refers to the force tracking task also includes the forefinger smaller forces forefinger larger forces, index finger, middle finger naturally force and the average distribution of forces of four modes of the index finger middle finger, the movement of the finger, and several different modes under the power spectrum of a preliminary analysis. Secondly, we explore rhythmic finger key movement in the time-frequency domain of the functional link between the cortex changes, the choice activity most strongly MLC15 channel MEG signal as reference, the rest of the sports-related cortical channel signal and the reference signal, coherence. Then, through the analysis of the coherence between MEG and sEMG (CMC) refers force tracking task motor cortex, discusses the role of the functional link between the cerebral cortex activity and muscle contraction control and coordination. Finally, the comparative analysis of the peak coherence coefficient by four different means force tracking task sEMG and finger force signals its peak frequency, strength level of coherence coefficient peak and peak frequency is not obvious, but different assignment mode, the above-mentioned two characteristic values ??exhibit significant differences, and the high peak average assignment mode more natural assignment mode, but the peak frequencies are significantly lower than the natural distribution pattern. The neuromuscular regulation research results show that: (1) With the increase in force levels, the beta band CMC increases, enhanced coordination between cortical activity and motor neurons to corticospinal interaction tends stable; drive mechanism of the central nervous system (cortex) and peripheral physiological tremor may result in the alpha band CMC exists and increases with force. (2) beta band CMC depend on the degree of precision of movement, so the same side of the beta-band CMC differences in the difficulty of two different allocation patterns may be by the force tracking and accuracy. (3) gamma band CMC with task difficulty increases, the average allocation force mode task difficulty related to ipsilateral and advanced neural activity enhancement requires more attention and more complex, continuous visual and rapid integration of somatosensory information, which led to the the gamma band's CMC with the increased difficulty and become strong. (4) finger coordination movement process sEMG / Force coherence amplitude modulation with coherent frequency modulation is not exactly the same neural information processing process, both may be independent of each other physiological processes, and different finger synergies as well as different force distribution mode neural regulation mechanism is different. Although the physiological basis of the CMC is unclear, but is generally considered CMC to reflect the transfer of information between the brain and muscles, and force control related. In addition, through the coherence between the event-related power spectral analysis and cortical neural activity has also been some tips: (1) the alpha band ERD with the increased force levels be transferred to the central and ipsilateral forces level increases, supplementary motor cortex and ipsilateral motor cortex neural activity along with enhancements that result. (2) beta band ERD / ERS with increasing task difficulty is enhanced, which is accompanied by an increase in the beta frequency band power spectrum due to the improvement of the sports performance, in the mode of the average distribution of forces, in order better to do the finger force tracking, need to focus more attention in order to facilitate the transmission of information between the corticospinal tract, resulting in the enhancement of the power spectrum. (3) more complex movement patterns related to the integration of a variety of information processing more gamma band and advanced information processing, thus resulting in the transfer by the low-frequency band to the gamma band with the task difficulty increased neural activity. Further explore the above conclusions to be through increased sample for statistical analysis.

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