检索结果-内蒙古大学图书馆

作者： Orcun Orkan OZCAN Universite de Strasbourg et Freiburg

学位级别：博士

The cerebellum integrates motor commands with somatosensory, vestibular, visual and auditory information for motor learning and coordination functions. The final step of this integration is done in the deep cerebellar nuclei (DCN) that process inputs from Purkinje cells (PC), mossy and climbing fibers, the two main excitatory inputs of the cerebellar cortex. We investigated the properties of PC connections to the different DCN cell types using optogenetic stimulation in L7-ChR2 mice combined with in vivo multi electrode extracellular recordings in lobule IV/V of the cerebellar cortex and in the medial nuclei. We identified two groups of DCN cells with significant differences in their action potential waveforms and firing rates which matched with the properties of GABAergic and non- GABAergic cells discriminated in vitro. The discharge of the DCN cells was correlated to the local field potentials and we found that DCN cells were phase locked to oscillations in the beta, gamma and high frequency bands. Although optogenetic stimulation of PCs resulted in the inhibition of the two groups of DCN cells (rate coding), spike times were controlled only for non-GABAergic cells. Moreover, local inhibition onto non-GABAergic cells was not observed in our in vivo experiments. Our results suggest that synchronized PC inputs drive the output of cerebellum by temporally controlling only non-GABAergic cells. Also, the internal DCN circuitry supports this phenomenon since GABAergic cells are not temporally controlled and the local inhibition they provide does not alter the time-locked output of the DCN.

关键词： Cerebellum optogenetic stimulation deep cerebellar nuclei Purkinje cells local inhibition GABAergic interneurons Glutamatergic projection cells in vivo electrophysiology rate coding temporal coding L7-ChR2 mice

来源：评论

学校读者我要写书评

暂无评论

rate Modulation of the Human Anconeus Muscle During High-Intensity Dynamic Fatigue of the Elbow Extensor Muscle Group

Rate Modulation of the Human Anconeus Muscle During High-Int...

引用

作者： Brianna L. Cowling University of Western Ontario

学位级别：硕士

PURPOSE: To evaluate anconeus motor unit firing rate (MUFR) as a function of time to task failure (TTF) during maximal velocity elbow extensions at a moderately heavy load. METHODS: Two fine-wire intramuscular electrode pairs were inserted into the anconeus to record MUFR in twelve male participants (25±3y). Individual MUs were tracked throughout a three-stage dynamic elbow extension fatigue protocol. Mean MUFR were calculated for the following time ranges: 0-15%, 45-60%, and 85-100% TTF. RESULTS: Following the fatigue task, with a mean TTF of 83s, peak power decreased 64% compared to baseline. Data from 20 anconeus MUs showed changes in MUFR from ~36 Hz (0-15% TTF) to ~28 Hz (45-60% TTF) to ~23 Hz (85-100% TTF). CONCLUSION: During high-intensity maximal velocity dynamic contractions, anconeus firing rates decreased substantially. The relative decrease in MUFR after this task is in accordance with that reported for sustained high-intensity isometric tasks in other muscles.

关键词： Motor neuron Discharge rate Concentric Velocity-dependent contraction rate coding

来源：评论

学校读者我要写书评

暂无评论

Variability and Randomness of the Instantaneous Firing rate

引用

FRONTIERS IN COMPUTATIONAL NEUROSCIENCE 2021年 15卷 620410页

作者： Tomar, Rimjhim Kostal, Lubomir Czech Acad Sci Inst Physiol Dept Computat Neurosci Prague Czech Republic Charles Univ Prague Med Fac 2 Prague Czech Republic

The apparent stochastic nature of neuronal activity significantly affects the reliability of neuronal coding. To quantify the encountered fluctuations, both in neural data and simulations, the notions of variability and randomness of inter-spike intervals have been proposed and studied. In this article we focus on the concept of the instantaneous firing rate, which is also based on the spike timing. We use several classical statistical models of neuronal activity and we study the corresponding probability distributions of the instantaneous firing rate. To characterize the firing rate variability and randomness under different spiking regimes, we use different indices of statistical dispersion. We find that the relationship between the variability of interspike intervals and the instantaneous firing rate is not straightforward in general. Counter-intuitively, an increase in the randomness (based on entropy) of spike times may either decrease or increase the randomness of instantaneous firing rate, in dependence on the neuronal firing model. Finally, we apply our methods to experimental data, establishing that instantaneous rate analysis can indeed provide additional information about the spiking activity.

关键词： variability randomness firing rate entropy rate coding neural coding temporal coding instantaneous firing rate

来源：评论

学校读者我要写书评

暂无评论

coding Capacity of Purkinje Cells With Different Schemes of Morphological Reduction

引用

FRONTIERS IN COMPUTATIONAL NEUROSCIENCE 2019年 13卷 29页

作者： An, Lingling Tang, Yuanhong Wang, Quan Pei, Qingqi Wei, Ran Duan, Huiyuan Liu, Jian K. Xidian Univ Sch Comp Sci & Technol Xian Shaanxi Peoples R China Univ Leicester Ctr Syst Neurosci Dept Neurosci Psychol & Behav Leicester Leics England

The brain as a neuronal system has very complex structures with a large diversity of neuronal types. The most basic complexity is seen from the structure of neuronal morphology, which usually has a complex tree-like structure with dendritic spines distributed in branches. To simulate a large-scale network with spiking neurons, the simple point neuron, such as the integrate-and-fire neuron, is often used. However, recent experimental evidence suggests that the computational ability of a single neuron is largely enhanced by its morphological structure, in particular, by various types of dendritic dynamics. As the morphology reduction of detailed biophysical models is a classic question in systems neuroscience, much effort has been taken to simulate a neuron with a few compartments to include the interaction between the soma and dendritic spines. Yet, novel reduction methods are still needed to deal with the complex dendritic tree. Here, using 10 individual Purkinje cells of the cerebellum from three species of guinea-pig, mouse and rat, we consider four types of reduction methods and study their effects on the coding capacity of Purkinje cells in terms of firing rate, timing coding, spiking pattern, and modulated firing under different stimulation protocols. We found that there is a variation of reduction performance depending on individual cells and species, however, all reduction methods can preserve, to some degree, firing activity of the full model of Purkinje cell. Therefore, when stimulating large-scale network of neurons, one has to choose a proper type of reduced neuronal model depending on the questions addressed. Among these reduction schemes, Branch method, that preserves the geometrical volume of neurons, can achieve the best balance among different performance measures of accuracy, simplification, and computational efficiency, and reproduce various phenomena shown in the full morphology model of Purkinje cells. Altogether, these results suggest that the B

关键词： Purkinje cell neuronal morphology dendritic model rate coding temporal coding multi-compartmental models

来源：评论

学校读者我要写书评

暂无评论

Deep spiking neural networks with integrate and fire neuron using steep switching device

引用

SOLID-STATE ELECTRONICS 2024年 214卷

作者： Woo, Sung Yun Pak, Sangyeon Lee, Sung-Tae Kyungpook Natl Univ Sch Elect Engn 80 Daehakro Daegu 41566 South Korea Hongik Univ Sch Elect & Elect Engn Seoul 04066 South Korea

Deep learning has shown impressive capabilities in tasks like speech recognition and image classification. However, modern deep neural networks often demand a significant number of weights and extensive computational resources, creating efficiency challenges for applications on edge devices. To address these issues, researchers have introduced deep spiking neural networks (DSNNs) that leverage specialized hardware for synapses and neurons. DSNNs offer a potential solution by improving efficiency in edge-device applications. In this paper, the hardware based DSNN with integrate and fire neuron using steep switching device was investigated. We propose integrate and fire neuron using steep switching device to implement rate coding as input encoding method. Because the steep switching device has double-gate, the threshold voltage of the neuron circuits can be adaptively controlled, which changes the rates of input pulse. Hence, the adjustment of the threshold of neuron can be employed to mitigate the accuracy deterioration resulting from the transformation from deep neural networks (DNNs) to DSNNs. In addition, the off-current of proposed integrate and fire neuron circuit decreases significantly as the steep switching device has steep subthreshold swing. A system simulation of a hardware based DSNN shows that the adjustable threshold of the neuron circuit can achieve a high inference accuracy of 98.36 % which is comparable to that obtained with software based DNN.

关键词： Deep spiking neural networks rate coding Neuron circuits Steep switching device

来源：评论

学校读者我要写书评

暂无评论

Spectro-Temporal Processing in a Two-Stream Computational Model of Auditory Cortex

引用

FRONTIERS IN COMPUTATIONAL NEUROSCIENCE 2020年 13卷 95页

作者： Zulfiqar, Isma Moerel, Michelle Formisano, Elia Maastricht Univ Maastricht Ctr Syst Biol Maastricht Netherlands Maastricht Univ Fac Psychol & Neurosci Dept Cognit Neurosci Maastricht Netherlands Maastricht Brain Imaging Ctr Maastricht Netherlands

Neural processing of sounds in the dorsal and ventral streams of the (human) auditory cortex is optimized for analyzing fine-grained temporal and spectral information, respectively. Here we use a Wilson and Cowan firing-rate modeling framework to simulate spectro-temporal processing of sounds in these auditory streams and to investigate the link between neural population activity and behavioral results of psychoacoustic experiments. The proposed model consisted of two core (A1 and R, representing primary areas) and two belt (Slow and Fast, representing rostral and caudal processing respectively) areas, differing in terms of their spectral and temporal response properties. First, we simulated the responses to amplitude modulated (AM) noise and tones. In agreement with electrophysiological results, we observed an area-dependent transition from a temporal (synchronization) to a rate code when moving from low to high modulation rates. Simulated neural responses in a task of amplitude modulation detection suggested that thresholds derived from population responses in core areas closely resembled those of psychoacoustic experiments in human listeners. For tones, simulated modulation threshold functions were found to be dependent on the carrier frequency. Second, we simulated the responses to complex tones with missing fundamental stimuli and found that synchronization of responses in the Fast area accurately encoded pitch, with the strength of synchronization depending on number and order of harmonic components. Finally, using speech stimuli, we showed that the spectral and temporal structure of the speech was reflected in parallel by the modeled areas. The analyses highlighted that the Slow stream coded with high spectral precision the aspects of the speech signal characterized by slow temporal changes (e.g., prosody), while the Fast stream encoded primarily the faster changes (e.g., phonemes, consonants, temporal pitch). Interestingly, the pitch of a speaker was encoded

关键词： auditory cortex sound processing dynamic neuronal modeling temporal coding rate coding

来源：评论

学校读者我要写书评

暂无评论

A simple neuronal model with intrinsic saturation of the firing frequency

引用

BIOSYSTEMS 2022年 222卷 104780页

作者： Tomar, Rimjhim Smith, Charles E. Lansky, Petr Czech Acad Sci Inst Physiol Videnska 1083 Prague 4 Czech Republic Charles Univ Prague Med Fac 2 V Uvalu 84 Prague 6 Czech Republic North Carolina State Univ Dept Stat 2311 Stinson Dr Raleigh NC 27695 USA

We present a comparison of the intrinsic saturation of firing frequency in four simple neural models: leaky integrate-and-fire model, leaky integrate-and-fire model with reversal potentials, two-point leaky integrate-and-fire model, and a two-point leaky integrate-and-fire model with reversal potentials. "Two-point"means that the equivalent circuit has two nodes (dendritic and somatic) instead of one (somatic only). The results suggest that the reversal potential increases the slope of the "firing rate vs input"curve due to a smaller effective membrane time constant, but does not necessarily induce saturation of the firing rate. The two-point model without the reversal potential does not limit the voltage or the firing rate. In contrast to the previous models, the two-point model with the reversal potential limits the asymptotic voltage and the firing rate, which is the main result of this paper. The case of excitatory inputs is considered first and followed by the case of both excitatory and inhibitory inputs.

关键词： rate coding Temporal coding Neuronal models Leaky integrate-and-fire Firing rate Reversal potential

来源：评论

学校读者我要写书评

暂无评论

Converting Data for Spiking Neural Network Training

引用

INTERNATIONAL JOURNAL OF ADVANCED COMPUTER SCIENCE AND APPLICATIONS 2023年第8期14卷 14-20页

作者： Sadovsky, Erik Jakubec, Maros Jarina, Roman Univ Zilina Dept Multimedia & Informat Commun Technol FEIT Zilina Slovakia

The application of spiking neural networks (SNNs) for processing visual and auditory data necessitate the conversion of traditional neural network datasets into a format suitable for spike-based computations. Existing datasets designed for conventional neural networks are incompatible with SNNs due to their reliance on spike timing and specific preprocessing requirements. This paper introduces a comprehensive pipeline that enables the conversion of common datasets into rate-coded spikes, meeting processing demands of SNNs. The proposed solution is evaluated on Spike-CNN trained on Time-to-First -Spike encoded MNIST and compared with the similar system trained on the neuromorphic dataset (N-MNIST). Both systems have comparative precision;however the proposed solution is more energy efficient than the system based on neuromorphic computing. Since, the proposed solution is not limited to any specific data form and can be applied to various types of audio/visual content. By providing a means to adapt existing datasets, this research facilitates the exploration and advancement of SNNs across different domains.

关键词： SNN rate coding spike timing data conversion MNIST

来源：评论

学校读者我要写书评

暂无评论

Editorial: Artificial Neural Networks as Models of Neural Information Processing

引用

FRONTIERS IN COMPUTATIONAL NEUROSCIENCE 2017年 11卷 114页

作者： van Gerven, Marcel Bohte, Sander Radboud Univ Nijmegen Donders Inst Brain Cognit & Behav Dept Artificial Intelligence Nijmegen Netherlands Ctr Wiskunde & Informat Dept Machine Learning Amsterdam Netherlands

Editorial on the Research Topic Artificial Neural Networks as Models of Neural Information Processing Introduction In artificial intelligence (AI), new advances make it possible that artificial neural networks (ANNs) learn to solve complex problems in a reasonable amount of time (LeCun et al., 2015). Folli et al. show that by allowing non-zero diagonal elements on the weight matrix, maximal storage capacity is obtained when the number of stored memory patterns exceeds the network size. The rate with which spikes are emitted is often mapped to the analog activation values of artificial neurons, but it is well-known that this relationship captures only part of the information processing in real neurons.

关键词： neural networks artificial intelligence computational neuroscience rate coding spiking neural networks

来源：评论

学校读者我要写书评

暂无评论

Quadriceps muscle strength, contractile properties, and motor unit firing rates in young and old men

引用

MUSCLE & NERVE 1999年第8期22卷 1094-1103页

作者： Roos, MR Rice, CL Connelly, DM Vandervoort, AA Ctr Activ & Aging London ON N6G 2M3 Canada Univ Western Ontario Fac Med Dept Anat & Cell Biol London ON Canada Univ Western Ontario Fac Hlth Sci Dept Phys Therapy London ON Canada

Changes with age in the voluntary static and dynamic strength of the quadriceps muscle group have been well characterized. and the importance of the muscle group for locomotion and independent living have been highlighted in both normal human aging and in clinical studies. Surprisingly few studies of this muscle group have described age-related changes in voluntary activation ability using twitch interpolation and changes in stimulated contractile properties, and none have assessed the influence of old age on motor unit firing rates. We compared in 13 young (mean age 26 years) and 12 old (mean age 80 years) men the voluntary isometric strength, stimulated contractile properties, and average steady state motor unit firing rates in the quadriceps muscle. Maximum voluntary contraction (MVC) force and twitch tension were similar to 50% lower in the old men, but contractile speed was only similar to 10% slower than in the young men. There was no difference in the ability of either group to activate the quadriceps to a high degree (94-96%), At all isometric force levels tested (10%, 25%, 50%, 75%, and 100% MVC), there were no differences in mean motor unit firing rates. In both groups, the range of firing rates was similar and not large (similar to 8 Hz at 10% MVC and 26 Hz at MVC), Thus, the substantial age-related weakness in this muscle does not seem to be related to changes in neural drive. (C) 1999 John Wiley & Sons, Inc.

关键词： electromyogram electromyography aging rate coding force generation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：