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On the simulation of large populations of neurons

JOURNAL OF COMPUTATIONAL NEUROSCIENCE 2000年第1期8卷 51-63页

作者： Omurtag, A Knight, BW Sirovich, L Mt Sinai Sch Med Lab Appl Math New York NY 10029 USA Rockefeller Univ New York NY 10021 USA

The dynamics of large populations of interacting neurons is investigated. Redundancy present in subpopulations of cortical networks is exploited through the introduction of a probabilistic description. A derivation of the kinetic equations for such subpopulations, under general transmembrane dynamics, is presented. The particular case of integrate-and-fire membrane dynamics is considered in detail. A variety of direct simulations of neuronal populations, under varying conditions and with as many as O(10(5)) neurons, is reported. Comparison is made with analogous kinetic equations under the same conditions. Excellent agreement, down to fine detail, is obtained. It is emphasized that no free parameters enter in the comparisons that are made.

关键词：动作电位/生理学细胞间通讯/生理学计算机模拟哺乳动物模型神经学神经通路/生理学神经元/生理学动物

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Analysis of neural spike trains with interspike interval reconstruction

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BIOLOGICAL CYBERNETICS 2000年第4期82卷 305-311页

作者： Suzuki, H Aihara, K Murakami, J Shimozawa, T Univ Tokyo Dept Math Engn & Informat Phys Tokyo 1138656 Japan Japan Sci & Technol Corp CREST Kawaguchi Saitama 3320012 Japan Hokkaido Univ Res Inst Elect Sci Kita Ku Sapporo Hokkaido 0600812 Japan

As a method for the analysis of neural spike trains, we examine fundamental characteristics of interspike interval (ISI) reconstruction theoretically with a leaky-integrator neuron model and experimentally with cricket wind receptor cells. Both the input to the leaky integrator and the stimulus to the wind receptor cells are the time series generated from the Rossler system. By numerical analysis of the leaky integrator, it is shown that, even if ISI reconstruction is possible, sometimes the entire structure of the Rossler attractor may not be reconstructed with IST reconstruction. For analysis of the in vivo physiological responses of cricket wind receptor cells, we apply IST reconstruction, nonlinear prediction and the: surrogate data method to the experimental data. As a result of the analysis, it is found that there is a significant deterministic structure in the spike trains. By this analysis of physiological data, it is also shown that, even if ISI reconstruction is possible, the entire attractor may not be reconstructed.

关键词：动作电位/生理学算法计算机模拟傅里叶分析蟋蟀科机械感受器/生理学模型神经学神经元传入/生理学非线性动力学数值分析计算机辅助随机过程风动物

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A first-passage-time analysis of the periodically forced noisy leaky integrate-and-fire model

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BIOLOGICAL CYBERNETICS 2000年第4期83卷 327-340页

作者： Shimokawa, T Pakdaman, K Takahata, T Tanabe, S Sato, S Osaka Univ Grad Sch Engn Sci Toyonaka Osaka 5608531 Japan

We present a general method for the analysis of the discharge trains of periodically forced noisy leaky integrate-and-fire neuron models. This approach relies on the iterations of a stochastic phase transition operator that generalizes the phase transition function used for the study of periodically forced deterministic oscillators to noisy systems. The kernel of this operator is defined in terms of the the first passage time probability density function of the Ornstein Uhlenbeck process through a suitable threshold. Numerically, it is computed as the solution of a singular integral equation. It is shown that, for the noisy system, quantities such as the phase distribution (cycle histogram), the interspike interval distribution, the autocorrelation function of the intervals, the autocorrelogram and the power spectrum density of the spike train, as well as the input-output cross-correlation and cross-spectral density can all be computed using the stochastic phase transition operator. A detailed description of the numerical implementation of the method, together with examples, is provided.

关键词：动作电位/生理学控制论模型神经学神经元传入/生理学周期性概率随机过程

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The dynamics of a neuronal culture of dissociated cortical neurons of neonatal rats

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BIOLOGICAL CYBERNETICS 2000年第1期83卷 1-20页

作者： Jimbo, Y Kawana, A Parodi, P Torre, V INFM I-34014 Trieste Italy SISSA I-34014 Trieste Italy NTT Basic Res & Telephone Co Atsugi Kanagawa 24301 Japan

Neuronal networks of dissociated cortical neurons from neonatal rats were cultured over a multielectrode dish with 64 active sites, which were used both for recording the electrical activity and for stimulation. After about 4 weeks of culture, a dense network of neurons had developed and their electrical activity was studied. When a brief voltage pulse was applied to one extracellular electrode, a clear electrical response was evoked over almost the entire network. When a strong voltage pulse was used, the response was composed of an early phase, terminating within 25 ms, and a late phase which could last several hundreds of milliseconds. Action potentials evoked during the early phase occurred with a precise timing with a small jitter and the electrical activity initiated by a localized stimulation diffused significantly over the network. In contrast, the late phase was characterized by the occurrence of clusters of electrical activity with significant spatio-temporal fluctuations. The late phase was suppressed by adding small amounts of D(-)-2-amino-5-phosphonovaleric acid to the extracellular medium, or by increasing the amount of extracellular Mg2+. The electrical activity of the network was substantially increased by the addition of bicuculline to the extracellular medium. The results presented here show that the neuronal network may exist in two different dynamical states: one state in which the neuronal network behaves as a non-chaotic deterministic system and another state where the system exhibits large spatio-temporal fluctuations, characteristic of stochastic or chaotic systems.

关键词：动作电位/生理学动物新生细胞培养的大脑皮质/细胞学导电性电生理学模型神经学神经元/细胞学神经元/生理学非线性动力学随机过程动物大鼠

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An interspike interval method for computing phase locking from neural firing

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BIOLOGICAL CYBERNETICS 2000年第4期82卷 283-290页

作者： Meyer-Bäse, U Meyer-Bäse, A Scheich, H Univ Florida Digital Signal Proc Grp ECE Gainesville FL 32611 USA Fed Inst Neurobiol D-39008 Magdeburg Germany

Inner hair cells (IHCs) transform the mechanical movements of the basilar membrane into electrical impulses. The impulse coding of the IHCs is the main information carrier in the auditory process and is the basis for improvements of cochlea implants as well as for low rate, high-quality speech processing and compression. This paper shows how to compute the speech signal from the neural firing based on the analysis of the interspike interval histogram. This new approach solves problems that other standard analysis methods do not solve sufficiently well.

关键词：动作电位/生理学算法耳蜗植入物/标准计算机模拟听力/生理学模型神经学信号处理计算机辅助言语知觉/生理学人类

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Visual channels, Hebbian assemblies and the effect of Hebb's rule

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BIOLOGICAL CYBERNETICS 2000年第5期82卷 401-413页

作者： Mortensen, U Nachtigall, C

A model of sensory learning is proposed that is based upon Hebb's rule, where Hebb's rule has been generalised by introducing a stabilising function representing some feedback process within or at the adapting (cortical) neuron, preventing synaptic weights from increasing without limit. It will be shown that neurons adapting according to this stabilised Hebb rule will turn into a matched filter for that part of the stimulus pattern that covers the receptive field of neuron. It follows that the presentation of a stimulus pattern may imply the formation of a set of neurons with overlapping receptive fields, where each neuron has adapted to a certain part of the stimulus. Making simplifying assumptions about the detection process, the model will be illustrated, fitting it to data from Meinhardt and Mortensen [Meinhardt G, Mortensen U (1998) Biol Cybern 79:413-425] which are not compatible with the classical matched filter model introduced by Hauske et al. [Hauske G, Wolf W, Lupp U (1976) Biol Cybern 22:181-188].

关键词：动作电位/生理学适应生理学/生理学反馈/生理学模型神经学神经元传入/生理学视野/生理学

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A simple latency-dependent spiking-neuron model of cricket phonotaxis

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BIOLOGICAL CYBERNETICS 2000年第3期82卷 247-269页

作者： Webb, B Scutt, T Univ Nottingham Dept Psychol Nottingham NG7 2RD England Univ Nottingham ICL Inst IT Nottingham NG7 2RD England

A simple hypothesis regarding the recognition behaviour of crickets for conspecific songs is implemented in a dynamic simulation of spiking neurons and tested on a robot base. The model draws on data from cricket neurophysiology but requires only four neurons to reproduce a wide range of the observed behaviour. The directional response depends on relative latencies in firing onset, and the 'recognition' emerges from the implicit filtering properties of leaky-integrate-and-fire neurons. Experimental conditions reproduced include tests of syllable rate preference, song from above with sound from one side, and choice between songs. The robot produces behaviour closely comparable to the cricket in all but a 'split-song' condition. A number of properties can be observed in the neural circuit that correspond to cricket neurophysiology including apparent 'recognition neurons'. Limitations of the model, extensions and alternative models are discussed.

关键词：动作电位/生理学动物交往计算机模拟蟋蟀科/生理学模型神经学运动活动/生理学神经元/生理学反应时间/生理学机器人声定位/生理学种特异性动物女(雌)性男(雄)性

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Intracellular Ca²⁺ release contributes to automaticity in cat atrial pacemaker cells

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JOURNAL OF PHYSIOLOGY-LONDON 2000年第2期524卷 415-422页

作者： Hüser, J Blatter, LA Lipsius, SL Loyola Univ Med Ctr Dept Physiol Stritch Sch Med Maywood IL 60153 USA

1. The cellular mechanisms governing cardiac atrial pacemaker activity are not clear. In the present study we used perforated patch voltage clamp and confocal fluorescence microscopy to study the contribution of intracellular Ca2+ release to automaticity of pacemaker cells isolated from cat right atrium. 2. In spontaneously beating pacemaker cells, an increase in subsarcolemmal intracellular Ca2+ concentration occurred concomitantly with the last third of diastolic depolarization due to local release of Ca2+ from the sarcoplasmic reticulum (SR), i.e. Ca2+ sparks. Nickel (Ni2+;25-50 mu M), a blocker of low voltage-activated T-type Ca2+ current (I-Ca,I-T), decreased diastolic depolarization, prolonged pacemaker cycle length and suppressed diastolic Ca2+ release. 3. Voltage clamp analysis indicated that the diastolic Ca2+ release was voltage dependent and triggered at about -60 mV. Ni2+ suppressed low voltage-activated Ca2+ release. Moreover, low voltage-activated Ca2+ release was paralleled by a slow inward current presumably due to stimulation of Naf-Ca2+ exchange (INa-Ca). Low voltage-activated Ca2+ release was found in both sino-atrial node and latent atrial pacemaker cells but not in working atrial myocytes. 4. These findings suggest that low voltage-activated I-Ca,I-T triggers subsarcolemmal Ca2+ sparks, which in turn stimulate INa-Ca to depolarize the pacemaker potential to threshold. This novel mechanism indicates a pivotal role for I-Ca,I-T and subsarcolemmal intracellular Ca2+ release in normal atrial pacemaker activity and may contribute to the development of ectopic atrial arrhythmias.

关键词：动作电位/生理学心房功能生物钟/生理学钙/代谢钙/生理学电生理学心脏/药物作用心脏/生理学心房/细胞学心房/代谢显微镜检查共焦显微镜检查荧光心肌/细胞学心肌/代谢镍/药理学膜片钳术动物猫女(雌)性男(雄)性

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Intrinsic and extrinsic modulation of a single central pattern generating circuit

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JOURNAL OF NEUROPHYSIOLOGY 2000年第3期84卷 1186-1193页

作者： Morgan, PT Perrins, R Lloyd, PE Weiss, KR Mt Sinai Sch Med Dept Physiol & Biophys New York NY 10029 USA Univ Bristol Dept Biol Sci Bristol BS8 1U9 Avon England Univ Chicago Dept Pharmacol Sci Chicago IL 60637 USA Univ Chicago Comm Neurobiol Chicago IL 60637 USA

Intrinsic and extrinsic neuromodulation are both thought to be responsible for the flexibility of the neural circuits (central pattern generators) that control rhythmic behaviors. Because the two forms of modulation have been studied in different circuits, it has been difficult to compare them directly. We find that the central pattern generator for biting in Aplysia is modulated both extrinsically and intrinsically. Both forms of modulation increase the frequency of motor programs and shorten the duration of the protraction phase. Extrinsic modulation is mediated by the serotonergic metacerebral cell (MCC) neurons and is mimicked by application of serotonin. Intrinsic modulation is mediated by the cerebral peptide-2 (CP-2) containing CBI-2 interneurons and is mimicked by application of CP-2. Since the effects of CBI-2 and CP-2 occlude each other, the modulatory actions of CBI-2 may be mediated by CP-2 release. Although the effects of intrinsic and extrinsic modulation are similar, the neurons that mediate them are active predominantly at different times, suggesting a specialized role for each system. Metacerebral cell (MCC) activity predominates in the preparatory (appetitive) phase and thus precedes the activation of CBI-2 and biting motor programs. Once the CBI-2s are activated and the biting motor program is initiated, MCC activity declines precipitously. Hence extrinsic modulation prefacilitates biting, whereas intrinsic modulation occurs during biting. Since biting inhibits appetitive behavior, intrinsic modulation cannot be used to prefacilitate biting in the appetitive phase. Thus the sequential use of extrinsic and intrinsic modulation may provide a means for premodulation of biting without the concomitant disruption of appetitive behaviors.

关键词：动作电位/药物作用动作电位/生理学海螺电刺激摄食行为/生理学神经节无脊椎动物/药物作用神经节无脊椎动物/生理学本能神经通路/药物作用神经通路/生理学神经肽类/代谢神经肽类/药理学周期性血清素/代谢血清素/药理学动物

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Multistability in recurrent neural loops arising from delay

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JOURNAL OF NEUROPHYSIOLOGY 2000年第2期84卷 975-985页

作者： Foss, J Milton, J Univ Chicago Dept Neurol Chicago IL 60637 USA Univ Chicago Comm Neurobiol Chicago IL 60637 USA

The dynamics of a recurrent inhibitory neural loop composed of a periodically spiking Aplysia motoneuron reciprocally connected to a computer are investigated as a function of the time delay, tau, for propagation around the loop. It is shown that for certain choices of tau, multiple qualitatively different neural spike trains co-exist. A mathematical model is constructed for the dynamics of this pulsed-coupled recurrent loop in which all parameters are readily measured experimentally: the phase resetting curve of the neuron for a given simulated postsynaptic current and tau. For choices of the parameters for which multiple spiking patterns co-exist in the experimental paradigm, the model exhibits multistability. Numerical simulations suggest that qualitatively similar results will occur if the motoneuron is replaced by several other types of neurons and that once tau becomes sufficiently long, multistability will be the dominant form of dynamical behavior. These observations suggest that great care must be taken in determining the etiology of qualitative changes in neural spiking patterns, particularly when propagation times around polysynaptic loops are long.

关键词：动作电位/生理学海螺计算机模拟反馈/生理学模型神经学运动神经元/生理学周期性反应时间/生理学动物

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