OMORI Toshiaki | ![]() |
Graduate School of Engineering / Department of Electrical and Electronic Engineering | |
Associate Professor | |
Electro-Communication Engineering |
Toshiaki Omori received his Ph.D. degree in Information Science from Tohoku University in 2004. He was a predoctoral research fellow of Japan Society of the Promotion of Science (JSPS) from 2003 to 2004, a postdoctoral researcher at Japan Science and Technology Agency from 2004 to 2006, and a postdoctoral research fellow of JSPS from 2006 to 2008. He was a visiting researcher at University of Arizona, U.S.A. in 2007. He became a research assistant professor and an assistant professor at the University of Tokyo in 2008. He is currently an associate professor at the Graduate School of Engineering, Kobe University. His research interests include machine learning theory and its applications, probabilistic information processing, and computational neuroscience.
Oct. 2022 国立大学法人神戸大学 令和4年度学長表彰
Nov. 2018 第40回日本比較生理生化学会 発表賞会長賞
Oct. 2018 第52回日本味と匂学会 優秀発表賞
Oct. 2017 Best Paper Award, 18th International Symposium on Advanced Intelligent Systems
Sep. 2014 情報科学技術フォーラム FIT奨励賞
May 2014 Achievement Award [Electrical Engineering], The Japan Electric Association Kansai Branch
Apr. 2012 RIKEN Appreciation Letter from President
Jun. 2011 情報処理学会 論文賞
Nov. 2010 独立行政法人理化学研究所 理事長感謝状
Sep. 2010 計測自動制御学会 生体・生理工学部会研究奨励賞
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© 2019, Springer Nature Switzerland AG. Surface heterogeneous reactions are chemical reactions with conjugation of multiple phases, and they have the intrinsic nonlinearity of their dynamics caused by the effect of surface-area between different phases. We propose a sparse modeling approach for extracting nonlinear dynamics of surface heterogeneous reactions from noisy observable data. We employ sparse modeling algorithm and sequential Monte Carlo algorithm to partial observation problem, in order to simultaneously extract substantial reaction terms and surface models from a number of candidates. Using our proposed method, we show that the rate constants of dissolution and precipitation reactions, which are typical examples of surface heterogeneous reactions, necessary surface models and reaction terms underlying observable data were successfully estimated only from the observable temporal changes in the concentration of the dissolved intermediate product.
Dec. 2019, Lecture Notes in Computer Science, 11954, 380 - 391[Refereed]
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Ants are known to use a colony-specific blend of cuticular hydrocarbons (CHCs) as a pheromone to discriminate between nestmates and non-nestmates and the CHCs were sensed in the basiconic type of antennal sensilla (S. basiconica). To investigate the functional design of this type of antennal sensilla, we observed the ultra-structures at 2D and 3D in the Japanese carpenter ant, Camponotus japonicus, using a serial block-face scanning electron microscope (SBF-SEM), and conventional and high-voltage transmission electron microscopes. Based on the serial images of 352 cross sections of SBF-SEM, we reconstructed a 3D model of the sensillum revealing that each S. basiconica houses > 100 unbranched dendritic processes, which extend from the same number of olfactory receptor neurons (ORNs). The dendritic processes had characteristic beaded-structures and formed a twisted bundle within the sensillum. At the "beads," the cell membranes of the processes were closely adjacent in the interdigitated profiles, suggesting functional interactions via gap junctions (GJs). Immunohistochemistry with anti-innexin (invertebrate GJ protein) antisera revealed positive labeling in the antennae of C. japonicus. Innexin 3, one of the five antennal innexin subtypes, was detected as a dotted signal within the S. basiconica as a sensory organ for nestmate recognition. These morphological results suggest that ORNs form an electrical network via GJs between dendritic processes. We were unable to functionally certify the electric connections in an olfactory sensory unit comprising such multiple ORNs; however, with the aid of simulation of a mathematical model, we examined the putative function of this novel chemosensory information network, which possibly contributes to the distinct discrimination of colony-specific blends of CHCs or other odor detection.
Sep. 2018, Frontiers in Cellular Neuroscience, 12, 310 - 310, English, International magazine[Refereed]
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Slow feature analysis (SFA) is a time-series analysis method for extracting slowly-varying latent features from multidimensional data. A recent study proposed a probabilistic framework of SFA using the Bayesian statistical framework. However, the conventional probabilistic framework of SFA can not accurately extract the slow feature in noisy environments since its marginal likelihood function was approximately derived under the assumption that there exists no observation noise. In this paper, we propose a probabilistic framework of SFA with rigorously derived marginal likelihood function. Here, we rigorously derive the marginal likelihood function of the probabilistic framework of SFA by using belief propagation. We show using numerical data that the proposed probabilistic framework of SFA can accurately extract the slow feature and underlying parameters for the latent dynamics simultaneously even under noisy environments.
PHYSICAL SOC JAPAN, Aug. 2017, Journal of the Physical Society of Japan, 86 (8), English[Refereed]
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It is essential to extract nonlinear dynamics from time-series data as an inverse problem in natural sciences. We propose a Bayesian statistical framework for extracting nonlinear dynamics of surface heterogeneous reactions from sparse and noisy observable data. Surface heterogeneous reactions are chemical reactions with conjugation of multiple phases, and they have the intrinsic nonlinearity of their dynamics caused by the effect of surface-area between different phases. We adapt a belief propagationmethod and an expectation-maximization (EM) algorithm to partial observation problem, in order to simultaneously estimate the time course of hidden variables and the kinetic parameters underlying dynamics. The proposed belief propagation method is performed by using sequential Monte Carlo algorithm in order to estimate nonlinear dynamical system. Using our proposed method, we show that the rate constants of dissolution and precipitation reactions, which are typical examples of surface heterogeneous reactions, as well as the temporal changes of solid reactants and products, were successfully estimated only from the observable temporal changes in the concentration of the dissolved intermediate product.
AMER PHYSICAL SOC, Sep. 2016, PHYSICAL REVIEW E, 94 (3), English[Refereed]
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A research project, called "the Initiative for High-dimensional Data-Driven Science through Deepening of Sparse Modeling" is introduced. A concept, called the three levels of data-driven science, is proposed to untie the complicated relation between many fields and many methods. This concept claims that any problem of data analysis should be discussed at different three levels: computational theory, modeling, and representation/algorithm. Based on the concept, how to choose a suitable method among several candidates is discussed through our study on spectral deconvolution. In addition, how to find a universal problem across the disciplines is presented by explaining our proposed ES-SVM method. Moreover, it is illustrated that the hierarchical structure of data analysis should be visualized and shared. From these discussions, we believe that data-driven science is mother of science, namely, a scientific framework that drives many fields of science.
IOP PUBLISHING LTD, 2016, Journal of Physics: Conference Series, 699, English[Refereed]
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We propose a data-driven statistical method for extracting nonlinear spatiotemporal membrane dynamics of active dendrites. We employ a framework of probabilistic information processing to extract the nonlinear spatiotemporal dynamics obeying the reaction-diffusion equation from partially observable data. By employing sequential Monte-Carlo method and other statistical methods, membrane dynamics and their underlying electrical properties are simultaneously estimated in the proposed method. Using the proposed method, we show that nonlinear spatiotemporal dynamics in active dendrites can be extracted from partially observable data.
IOP PUBLISHING LTD, 2016, Journal of Physics: Conference Series, 699, English[Refereed]
International conference proceedings
Metastable minerals commonly form during reactions between water and rock. The nucleation mechanism of polymorphic phases from solution are explored here using a two-dimensional Potts model. The model system is composed of a solvent and three polymorphic solid phases. The local state and position of the solid phase are updated by Metropolis dynamics. Below the critical temperature, a large cluster of the least stable solid phase initially forms in the solution before transitioning into more-stable phases following the Ostwald step rule. The free-energy landscape as a function of the modal abundance of each solid phase clearly reveals that before cluster formation, the least stable phase has an energetic advantage because of its low interfacial energy with the solution, and after cluster formation, phase transformation occurs along the valley of the free-energy landscape, which contains several minima for the regions of three phases. Our results indicate that the solid-solid and solid-liquid interfacial energy contribute to the formation of the complex free-energy landscape and nucleation pathways following the Ostwald step rule.
AMER PHYSICAL SOC, Oct. 2015, PHYSICAL REVIEW E, 92 (4), English[Refereed]
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The spike-triggered average (STA) and phase response curve characterize the response properties of single neurons. A recent theoretical study proposed a method to estimate the phase response curve by means of linear regression with Fourier basis functions. In this study, we propose a method to estimate the STA by means of sparse linear regression with Fourier and polynomial basis functions. In the proposed method, we use sparse estimation with L1 regularization to extract substantial basis functions for the STA. We show using simulated data that the proposed method achieves more accurate estimation of the STA than the simple trial average used in conventional method.
Information Processing Society of Japan, 2014, IPSJ Online Transactions, 7 (2014), 52 - 58, English[Refereed]
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For the purpose of elucidating the neural coding process based on the neural excitability mechanism, researchers have recently investigated the relationship between neural dynamics and the spike triggered stimulus ensemble (STE). Ermentrout et al. analytically derived the relational equation between the phase response curve (PRC) and the spike triggered average (STA). The STA is the first cumulant of the STE. However, in order to understand the neural function as the encoder more explicitly, it is necessary to elucidate the relationship between the PRC and higher-order cumulants of the STE. In this paper, we give a general formulation to relate the PRC and the nth moment of the STE. By using this formulation, we derive a relational equation between the PRC and the spike triggered covariance (STC), which is the covariance of the STE. We show the effectiveness of the relational equation through numerical simulations and use the equation to identify the feature space of the rat hippocampal CA1 pyramidal neurons from their PRCs. Our result suggests that the hippocampal CA1 pyramidal neurons oscillating in the theta frequency range are commonly sensitive to inputs composed of theta and gamma frequency components.
PUBLIC LIBRARY SCIENCE, Nov. 2012, PLOS ONE, 7 (11), English[Refereed]
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With developments in optical imaging over the past decade, statistical methods for estimating dendritic membrane resistance from observed noisy signals have been proposed. In most of previous studies, membrane resistance over a dendritic tree was assumed to be constant, or membrane resistance at a point rather than that over a dendrite was investigated. Membrane resistance, however, is actually not constant over a dendrite. In a previous study, a method was proposed in which membrane resistance value is expressed as a non-constant function of position on dendrite, and parameters of the function are estimated. Although this method is effective, it is applicable only when the appropriate function is known. We propose a statistical method, which does not express membrane resistance as a function of position on dendrite, for estimating membrane resistance over a dendrite from observed membrane potentials. We use the Markov random field (MRF) as a prior distribution of the membrane resistance. In the MRF, membrane resistance is not expressed as a function of position on dendrite, but is assumed to be smoothly varying along a dendrite. We apply our method to synthetic data to evaluate its efficacy, and show that even when we do not know the appropriate function, our method can accurately estimate the membrane resistance.
Information Processing Society of Japan, 2012, IPSJ Online Transactions, 5 (2012), 186 - 191, English[Refereed]
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We sought to measure infinitesimal phase response curves (iPRCs) from rat hippocampal CA1 pyramidal neurons. It is difficult to measure iPRCs from noisy neurons because of the dilemma that either the linearity or the signal-to-noise ratio of responses to external perturbations must be sacrificed. To overcome this difficulty, we used an iPRC measurement model formulated as the Langevin phase equation (LPE) to extract iPRCs in the Bayesian scheme. We then simultaneously verified the effectiveness of the measurement model and the reliability of the estimated iPRCs by demonstrating that LPEs with the estimated iPRCs could predict the stochastic behaviors of the same neurons, whose iPRCs had been measured, when they were perturbed by periodic stimulus currents. Our results suggest that the LPE is an effective model for real oscillating neurons and that many theoretical frameworks based on it may be applicable to real nerve systems. © 2011 American Physical Society.
03 Oct. 2011, Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 84 (4), English[Refereed]
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We sought to measure infinitesimal phase response curves (iPRCs) from rat hippocampal CA1 pyramidal neurons. It is difficult to measure iPRCs from noisy neurons because of the dilemma that either the linearity or the signal-to-noise ratio of responses to external perturbations must be sacrificed. To overcome this difficulty, we used an iPRC measurement model formulated as the Langevin phase equation (LPE) to extract iPRCs in the Bayesian scheme. We then simultaneously verified the effectiveness of the measurement model and the reliability of the estimated iPRCs by demonstrating that LPEs with the estimated iPRCs could predict the stochastic behaviors of the same neurons, whose iPRCs had been measured, when they were perturbed by periodic stimulus currents. Our results suggest that the LPE is an effective model for real oscillating neurons and that many theoretical frameworks based on it may be applicable to real nerve systems.
AMER PHYSICAL SOC, Oct. 2011, PHYSICAL REVIEW E, 84 (4), English[Refereed]
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A calcium imaging method has superior ability in recording of spatial temporal variations in ion concentration. However, it has two major problems. First, the imaging signals are very noisy. Second, the observation data are only the fluorescence intensities of Ca2+ indicator dyes that provide indirect information about the Ca2+ concentration. We develop a nonlinear state-space model for Ca imaging series involving Ca2+ kinetics and a noisy fluorescence intensity pickup process. We devise recursive update algorithms for estimating the Ca2+ concentration and Ca2+ flux, and give the expectation-maximization algorithm for inferring model parameters.
PHYSICAL SOC JAPAN, Dec. 2010, JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 79 (12), English[Refereed]
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Spike-triggered analysis is a statistical method used to elucidate encoding properties in neural systems by estimating the statistical structure of input stimulus preceding spikes. A recent numerical study suggested that the profile of the spike-triggered average (STA) changes depending on whether the mean input stimuli are subthreshold or suprathreshold. Here we analytically verify the difference between subthreshold STA and suprathreshold STA by using the spike response model (SRM). We show by moment expansion that the suprathreshold STA is proportional to the first derivative of the response kernel, and that the subthreshold STA is expressed by a linear combination of the response kernel and its first derivative. We verify whether the analytical results obtained from the SRM can be applied to a multicompartment model with Hodgkin-Huxley type dynamics. © 2010 The American Physical Society.
01 Feb. 2010, Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 81 (2), English[Refereed]
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Under physiological and artificial conditions, the dendrites of neurons can be exposed to electric fields Recent experimental studies suggested that the membrane resistivity of the distal apical dendrites of cortical and hippocampal pyramidal neurons may be significantly lower than that of the proximal dendrites and the soma To understand the behavior of dendrites in time-varying extracellular electric fields, we analytically solved cable equations for finite cylindrical cables with and without a leak conductance attached to one end by employing the Green's function method The solution for a cable with a leak at one end for direct-current step electric fields shows a reversal in polarization at the leaky end, as has been previously shown by employing the separation of variables method and Fourier series expansion The solution for a cable with a leak at one end for alternating-current electric fields reveals that the leaky end shows frequency preference in the response amplitude Our results predict that a passive dendrite with low resistivity at the distal end would show frequency preference in response to sinusoidal extracellular local field potentials The Green's function obtained in our study can be used to calculate response for any extracellular electric field
CELL PRESS, Feb. 2010, BIOPHYSICAL JOURNAL, 98 (4), 524 - 533, English[Refereed]
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Spike-triggered analysis is a statistical method used to elucidate encoding properties in neural systems by estimating the statistical structure of input stimulus preceding spikes. A recent numerical study suggested that the profile of the spike-triggered average (STA) changes depending on whether the mean input stimuli are subthreshold or suprathreshold. Here we analytically verify the difference between subthreshold STA and suprathreshold STA by using the spike response model (SRM). We show by moment expansion that the suprathreshold STA is proportional to the first derivative of the response kernel, and that the subthreshold STA is expressed by a linear combination of the response kernel and its first derivative. We verify whether the analytical results obtained from the SRM can be applied to a multicompartment model with Hodgkin-Huxley type dynamics.
AMER PHYSICAL SOC, Feb. 2010, PHYSICAL REVIEW E, 81 (2), English[Refereed]
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An associative memory model and a neural network model with a Mexican-hat type interaction are two major attractor neural network models. The associative memory model has discretely distributed fixed-point attractors, and achieves a discrete information representation. On the other hand, a neural network model with a Mexican-hat type interaction uses a ring attractor to achieves a continuous information representation, which can be seen in the working memory in the prefrontal cortex and columnar activity in the visual cortex. In the present study, we propose a neural network model that achieves discrete and continuous information representation. We use a statistical-mechanical analysis to find that a localized retrieval phase exists in the proposed model, where the memory pattern is retrieved in the localized Subpopulation of the network. In the localized retrieval phase, the discrete and continuous information representation is achieved by using the orthogonality of the memory patterns and the neutral stability of fixed points along the positions of the localized retrieval. The obtained phase diagram suggests that the anti ferromagnetic interaction and the external field are important for generating the localized retrieval phase.
PHYSICAL SOC JAPAN, Nov. 2009, JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 78 (11), English[Refereed]
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Specific membrane resistance (R(m)), distributed non-uniformly over the dendrite, has a substantial effect on neuronal information processing, since it is a major determinant in subthreshold-synaptic integration. From experimental data of dendritic excitatory postsynaptic potential (EPSP) spread, we previously reported that non-uniform R(m) distribution in hippocampal CA1 pyramidal neurons could be expressed as a step function. However, it remains unclear how steeply R(m) decreases. Here, we estimated the R(m) distribution using sigmoid function to evaluate the steepness of decrease in R(m). Simulations were performed to find the distribution which reproduced experimental voltage responses to extracellular electric field applied to CA1 slices, in contrast to the EPSP spread. Distribution estimated from the responses to electric field was a steep-sigmoid function, similar to that from the EPSP spread. R(m) in distal dendrite was estimated to be less than or similar to 10(3.5) Omega cm(2) whereas that in proximal dendrite/soma was greater than or similar to 10(4.5) Omega cm(2). Our results not only supported previous studies, but, surprisingly, implied that R(m) decreases at a location more distal, and that distal dendrite was leakier, than previous estimates by other groups. Simulations satisfactorily reproduced the responses to two distinct perturbations, suggesting that steep decrease in R. is reliable. Our study suggests that the non-uniform Rm distribution plays an important role in information processing for spatially segregated synaptic inputs. (C) 2009 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.
ELSEVIER IRELAND LTD, May 2009, NEUROSCIENCE RESEARCH, 64 (1), 83 - 95, English[Refereed]
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Many research groups have sought to measure phase response curves (PRCs) from real neurons. However, methods of estimating PRCs from noisy spike-response data have yet to be established. In this paper, we propose a Bayesian approach for estimating PRCs. First, we analytically obtain a likelihood function of the PRC from a detailed model of the observation process formulated as Langevin equations. Then we construct a maximum a posteriori (MAP) estimation algorithm based on the analytically obtained likelihood function. The MAP estimation algorithm derived here is equivalent to the spherical spin model. Moreover, we analytically calculate a marginal likelihood corresponding to the free energy of the spherical spin model, which enables us to estimate the hyper-parameters, i.e., the intensity of the Langevin force and the smoothness of the prior.
SPRINGER, Apr. 2009, JOURNAL OF COMPUTATIONAL NEUROSCIENCE, 26 (2), 185 - 202, English[Refereed]
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The Langevin phase model is an important canonical model for capturing coherent oscillations of neural populations However, little attention has been given to verifying its applicability In this paper, we demonstrate that the Langevin phase equation is an efficient model for neural oscillators by using the machine learning method in two steps. (a) Learning of the Langevin phase model We estimated the parameters of the Langevin phase equation, i.e. , a phase response curve and the intensity of white noise from physiological data measured in the hippocampal CA1 pyramidal neurons (b) Test of the estimated model. We verified whether a Fokker-Planck equation derived from the Langevin phase equation with the estimated parameters could capture the stochastic oscillatory behavior of the same neurons disturbed by periodic perturbations The estimated model could predict the neural behavior, so we can say that the Langevin phase equation is an efficient model for oscillating neurons
IOP PUBLISHING LTD, 2009, INTERNATIONAL WORKSHOP ON STATISTICAL-MECHANICAL INFORMATICS 2009 (IW-SMI 2009), 197 (012016), English[Refereed]
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A lossy data compression scheme for uniformly biased Boolean messages is investigated via statistical mechanics techniques. We utilize a treelike committee machine (committee tree) and a treelike parity machine (parity tree) whose transfer functions are nonmonotonic. The scheme performance at the infinite code length limit is analyzed using the replica method. Both committee and parity treelike networks are shown to saturate the Shannon bound. The Almeida-Thouless stability of the replica symmetric solution is analyzed, and the tuning of the nonmonotonic transfer function is also discussed.
AMER PHYSICAL SOC, Aug. 2008, PHYSICAL REVIEW E, 78 (2), English[Refereed]
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A lossy data compression scheme for uniformly biased Boolean messages is investigated via statistical mechanics techniques. The present paper utilize tree-like committee machine (committee tree) and tree-like parity machine (parity tree) whose transfer functions are non-monotonic, completing the study of the lossy compression scheme using perceptron-based decoder. The scheme performance at the infinite code length limit is analyzed using the replica method. Both committee and parity treelike networks are shown to saturate the Shannon bound.
IEEE, 2008, 2008 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY PROCEEDINGS, VOLS 1-6, 509 - +, English[Refereed]
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We propose a two-layered neural network model for oscillatory phenomena in the thalamic system and investigate an effect of neuromodulation due to the acetylcholine on the oscillatory phenomena by numerical simulations. The proposed model consists of a layer of the thalamic reticular neurons and that of the cholinergic neurons. We introduce a dynamics of concentration of the acetylcholine which depends on a state of the cholinergic neurons, and assume that the conductance of the thalamic reticular neurons is dynamically regulated by the acetylcholine. From the results obtained by numerical simulations, we find that a dynamical transition between a bursting state and a resting state occurs successively in the layer of the thalamic reticular neurons due to the acetylcholine. Therefore it turns out that the neuromodulation due to the acetylcholine is important for the dynamical state transition in the thalamic system.
PHYSICAL SOC JAPAN, Dec. 2004, JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 73 (12), 3489 - 3494, English[Refereed]
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We propose a neural network model of working memory with one-compartmental neurons and investigate its dynamical properties. We assume that the model consists of excitatory neurons and inhibitory neurons; all the neurons are connected to each other. The excitatory neurons are distinguished as several groups of selective neurons and one group of non-selective neurons. The selective neurons are assumed to form subpopulations in which each selective neuron belongs to only one of subpopulations. The non-selective neurons are assumed not to form any subpopulation. Synaptic strengths between neurons within a subpopulation are assumed to be potentiated. By the numerical simulations, persistent firing of neurons in a subpopulation emerges; the persistent firing corresponds to the retention of memory as one of the functions of working memory. We find that the strength of external input and the strength of N-methyl-D-aspartate synapse are important factors for dynamical behaviors of the network; for example, if we enhance the strength of the external input to a subpopulation while the persistent firing is occurring in other subpopulation, the persistent firing occurs in the subpopulation or is sustained against the external input. These results reveal that the neural network as for the function of the working memory is controlled by the neuromodulation and the external stimuli within the proposed model. We also find that the persistent time of firing of the selective neurons shows a kind of phase transition as a function of the degree of potentiation of synapses, (C) 2003 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, Mar. 2004, PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS, 334 (3-4), 600 - 614, English[Refereed]
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We propose a dynamical neural network model with excitatory neurons and inhibitory neurons for memory function in hippocampus and investigate the effect of inhibitory neurons on memory recall. The results by numerical simulations show that the introduction of inhibitory neurons improves the stability of the memory recall in the proposed model by supppressing the bursting of neurons.
PHYSICAL SOC JAPAN, Mar. 2004, JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 73 (3), 749 - 755, English[Refereed]
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We investigate some noise effect on a neural network model proposed by Araki and Aihara for the memory recall of dynamical patterns in the hippocampus and the entorhinal cortex; the noise effect is important since the release of transmitters at synaptic clefts, the operation of gate of ion channels and so on are known as stochastic phenomena. We consider two kinds of noise effect due to a deterministic noise and a stochastic noise. By numerical simulations, we find that reasonable values of noise give better performance on the memory recall of dynamical patterns. Furthermore we investigate the effect of the strength of external inputs on the memory recall.
PHYSICAL SOC JAPAN, Jun. 2002, JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 71 (6), 1598 - 1604, English[Refereed]
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We propose a hippocampal CA3 model with excitatory neurons and inhibitory neurons by using Hodgkin-Huxley equations and investigate oscillatory phenomena in the model. We assume that there are two layers of neurons with interlayer and intra-layer synaptic connections; one is a layer of excitatory neurons and the other a layer of inhibitory neurons. The results by numerical simulations show that theta and gamma oscillations occur on the layer of excitatory neurons and also on the layer of inhibitory neurons and reveal that synaptic strengths influence dominant oscillations on each layer. This implies that the interplay between the excitatory and the inhibitory neurons is essential for the generation of theta and gamma oscillations.
NANYANG TECHNOLOGICAL UNIV, 2002, ICONIP'02: PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON NEURAL INFORMATION PROCESSING, 1597 - 1601, English[Refereed]
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電子情報通信学会
情報処理学会
電気学会
計測自動制御学会
システム制御情報学会
米国電気電子学会(IEEE)
米国計算機学会(ACM)
日本物理学会
日本応用数理学会
日本神経回路学会
人工知能学会
日本神経科学学会
北米神経科学学会(Society for Neuroscience)
日本地球惑星科学連合
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Financial Chair, Organizing Committee, IEEE World Congress on Computational Intelligence 2024 (WCCI 2024)
2021 - Present情報処理学会論文誌 数理モデル化と応用編集委員会 編集委員
2018 - Present情報処理学会 数理モデル化と問題解決研究運営委員会 運営委員
2017 - PresentProgram Committee Member, 15th IEEE/ACIS International Conference on Computer and Information Science (2016)
2016 - 2016Organizing Committee Member, 23th International Conference on Neural Information Processings (2016)
2016 - 2016Program Committee Member, 21th International Conference on Neural Information Processings (2014)
2014 - 2014システム制御情報学会 編集委員
2014 - 2014平成25年(第68回)電気関係学会関西連合大会 実行委員
2013 - 2013電気学会 選挙管理委員会 委員
2013 - 2013日本物理学会 領域11 領域役員(統計・物基)
2013 - 2013電気学会 創立125周年記念事業委員会 委員
2013 - 2013電気学会 総務会議 委員
2013 - 2013第57回システム制御情報学会研究発表講演会(SCI'13) 実行委員
2012 - 2012電気学会 創立125周年記念事業実行委員会 委員
2012 - 2012電気学会 広報委員会 委員
2012 - 2012電気学会 編修専門第3部会 委員
2012 - 2012電気学会 関西支部 総務企画幹事
2012 - 2012, Secretary, Planning & General Affairs Kansai Branch The Institute of Electrical Engineers of JapanProgram Committee Member, 18th International Conference on Neural Information Processings (2011).
Program Committee Member, 17th International Conference on Neural Information Processings (2010).
Program Committee Member, 16th International Conference on Neural Information Processings (2009).
Technical Committee Member, 15th International Conference on Neural Information Processings (2008).
Program Committee Member, 20th International Conference on Neural Information Processings (2013)