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A simulation study on the relation between muscle motor unit numbers and the non-Gaussianity/non-linearity levels of surface electromyography

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Science China(Life Sciences) 2012年第11期55卷 958-967页

作者： ZHAO Yan LI DongXu College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China Science and Technology on Human Factors Engineering Laboratory China Astronaut Research and Training CenterBeijing 100094China

Recent research has demonstrated that surface electromyography （sEMG） signals have non-Gaussianity and non-linearity properties. It is known that more muscle motor units are recruited and firing rates （FRs） increase as exertion increases. A hy- pothesis was proposed that the Gaussianity test （Sg） and linearity test （St） levels of sEMG signals are associated with the num- ber of active motor units （nMUs） and the FR. The hypothesis has only been preliminarily discussed in experimental studies. We used a simulation sEMG model involving spatial （active MUs） and temporal （three FRs） information to test the hypothesis. Higher-order statistics （HOS） from the bi-frequency domain were used to perform Sg and St. Multivariate covariance analysis and a correlation test were employed to determine the nMUs-Sg relationship and the nMUs-St relationship. Results showed that nMUs, the FR, and the interaction of nMUs and the FR all influenced the Sg and St values. The nMUs negatively correlated to both the Sg and St values. That is, at the three FRs, sEMG signals tended to a more Gaussian and linear distribution as exertion and nMUs increased. The study limited experiment factors to the sEMG non-Gaussianity and non-linearity levels. The study quantitatively described nMUs and the FR of muscle that are not directly available from experiments. Our finding has guiding significance for muscle capability assessment and prosthetic control.

关键词： simulation surface electromyography model higher-order statistics motor unit firing rate

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Apelin-13 regulates electrical activity in the globus pallidus and induces postural changes in rats

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Neural Regeneration Research 2021年第11期16卷 2264-2268页

作者： Ying Wang Yan Xue Cui Liu Lei Chen Department of Physiology School of Basic MedicineQingdao UniversityQingdaoShandong ProvinceChina

The globus pallidus is the relay nucleus of the basal ganglia,and changes in its electrical activity can cause motor ***-13 is widely distributed in the central and peripheral nervous *** has been demonstrated that apelin-13 plays important roles in the regulation of blood pressure and other non-motor ***,its role in motor function has rarely been *** the present study,apelin-13(10μM/100μM)was injected into the globus pallidus of *** results showed that apelin-13 increased the spontaneous discharges in the majority of pallidal ***,an apelin-13-induced inhibitory effect on the firing rate was also observed in a few pallidal *** postural tests,after the systemic administration of haloperidol,unilateral pallidal injection of apelin-13 caused a contralateral ***,these findings suggest that apelin-13 regulates the electrical activity of pallidal neurons and thus participates in central motor control in *** study was approved by the Animal Ethics Committee of Qingdao University(approval No.20200615Wistar0451003020)on June 15,2020.

关键词： apelin-13 basal ganglion electrophysiology firing rate globus pallidus microinjection motor behavior movement disorder

A Hopfield-like hippocampal CA3 neural network model for studying associative memory in Alzheimer's disease

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Neural Regeneration Research 2010年第22期5卷 1694-1700页

作者： Wangxiong Zhao Qingli Qiao Dan Wang School of Biomedical Engineering Tianjin Medical University Tianjin 300070 China

Associative memory, one of the major cognitive functions in the hippocampal CA3 region, includes auto-associative memory and hetero-associative memory. Many previous studies have shown that Alzheimer＇s disease （AD） can lead to loss of functional synapses in the central nervous system, and associative memory functions in patients with AD are often impaired, but few studies have addressed the effect of AD on hetero-associative memory in the hippocampal CA3 region. In this study, based on a simplified anatomical structure and synaptic connections in the hippocampal CA3 region, a three-layered Hopfield-like neural network model of hippocampal CA3 was proposed and then used to simulate associative memory functions in three circumstances： normal, synaptic deletion and synaptic compensation, according to Ruppin＇s synaptic deletion and compensation theory. The influences of AD on hetero-associative memory were further analyzed. The simulated results showed that the established three-layered Hopfield-like neural network model of hippocampal CA3 has both auto-associative and hetero-associative memory functions. With increasing synaptic deletion level, both associative memory functions were gradually impaired and the mean firing rates of the neurons within the network model were decreased. With gradual increasing synaptic compensation, the associative memory functions of the network were improved and the mean firing rates were increased. The simulated results suggest that the Hopfield-like neural network model can effectively simulate both associative memory functions of the hippocampal CA3 region. Synaptic deletion affects both auto-associative and hetero-associative memory functions in the hippocampal CA3 region, and can also result in memory dysfunction. To some extent, synaptic compensation measures can offset two kinds of associative memory dysfunction caused by synaptic deletion in the hippocampal CA3 area.

关键词： hippocampal CA3 region Hopfield-like neural network associative memory Alzheimer's disease Izhkevich neuronal model firing rate

Stimulation of midbrain dopaminergic structures modifies firing rates of rat lateral habenula pain-activated neurons

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Stimulation of midbrain dopaminergic structures modifies fir...