Ichiro Tsuda

Ichiro Tsuda
Chubu University · Chubu University Academy of Emerging Sciences

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172
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Publications

Publications (172)
Chapter
The ability of the brain to generate complex spatiotemporal patterns with a specific timing is essential for motor learning and time series prediction. An approach that tries to replicate this ability using the self-sustained neural activity of a randomly connected recurrent neural network (reservoir) meets the difficulty of orbital instability. We...
Article
Full-text available
Mathematical and computational approaches were used to investigate dementia with Lewy bodies (DLB), in which recurrent complex visual hallucinations (RCVH) is a very characteristic symptom. Beginning with interpretative analyses of pathological symptoms of patients with RCVH-DLB in comparison with the veridical perceptions of normal subjects, we co...
Article
Objective To determine clinically ictal direct current (DC) shifts that can be identified by a time constant (TC) of 2 s and to delineate different types of DC shifts by different attenuation patterns between TC of 10 s and 2 s. Methods Twenty-one patients who underwent subdural electrode implantation for epilepsy surgery were investigated. For ha...
Article
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The focus of this article is the self-organization of neural systems under constraints. In 2016, we proposed a theory for self-organization with constraints to clarify the neural mechanism of functional differentiation. As a typical application of the theory, we developed evolutionary reservoir computers that exhibit functional differentiation of n...
Chapter
One of the most striking characteristics of the developing brain is functional differentiation, while emerging interactions develop between networking differentiated areas. To clarify the neural mechanism of functional differentiation, we constructed a mathematical model of self-organization with constraints. By casting different constraints, we in...
Article
Writing a history of a scientific theory is always difficult because it requires to focus on some key contributors and to “reconstruct” some supposed influences. In the 1970s, a new way of performing science under the name “chaos” emerged, combining the mathematics from the nonlinear dynamical systems theory and numerical simulations. To provide a...
Article
We propose an extended reservoir computer that shows the functional differentiation of neurons. The reservoir computer is developed to enable changing of the internal reservoir using evolutionary dynamics, and we call it an evolutionary reservoir computer. To develop neuronal units to show specificity, depending on the input information, the intern...
Article
Focusing on the developmental process of the brain, we propose a neural network model of functional differentiation including functional parcellation. We explain the emerging process of functional elements, of the system through the constraints, which act on the whole network system. We explain several kinds of differentiation, such as the differen...
Article
Cantor coding provides an information coding scheme for temporal sequences of events. In the hippocampal CA3–CA1 network, Cantor coding-like mechanism was observed in pyramidal neurons and the relationship between input pattern and recorded responses could be described as an iterated function system. However, detailed physiological properties of th...
Preprint
Full-text available
We propose an extended reservoir computer that shows the functional differentiation of neurons. The reservoir computer is developed to enable changing of the internal reservoir using evolutionary dynamics, and we call it an evolutionary reservoir computer. To develop neuronal units to show specificity, depending on the input information, the intern...
Article
Full-text available
In this paper, we propose a new method based on the dynamic mode decomposition (DMD) to find a distinctive contrast between the ictal and interictal patterns in epileptic electroencephalography (EEG) data. The features extracted from the method of DMD clearly capture the phase transition of a specific frequency among the channels corresponding to t...
Article
We attempted to create a mathematical model for neuronal differentiation. The present study was performed within the framework of self-organization with constraints by looking for an optimized informational unit. We treated networks of individual dynamical system units with an external input, which was provided by coupled one-dimensional maps with...
Article
Constrained chaos introduced into a three-module neural network having feedforward inter-module structure could have potential abilities to execute multiple tasks simultaneously. Each module consists of a large number of binary state (±1) neurons. The entire activity pattern (neuron state) is updated by recurrent rule under certain external input t...
Article
In the present study, we attempted to characterize two characteristic features within the dynamic behavior of wideband electrocorticography data, which were recorded as the brain waves of epilepsy, comprising high-frequency oscillations (HFOs) and interictal epileptic slow (red slow). The results of power spectrum and nonlinear time series analysis...
Chapter
Devil’s Advocate This paper addresses a provocative remark advocating the field theory of Kozma and Freeman, by proposing a new mathematical model for functional differentiation in neural systems. The computational result suggests the presence of self-organization of the second kind.
Article
It is not at all uncommon to see people, animals, or objects that other people cannot perceive. Data from studies of pathological hallucinations suggests that distributed functional changes within visual and associated systems increases the risk of visual hallucinations, though how this occurs is not yet clear. Candidate theories developed in the c...
Article
Full-text available
This study proposes mathematical models for functional differentiations that are viewed as self-organization with external constraints. From the viewpoint of system development, the present study investigates how system components emerge under the presence of constraints that act on a whole system. Cell differentiation in embryos and functional dif...
Chapter
Neural oscillations with various frequency bands have been observed in several brain regions during behavioral and cognitive tasks. Communication via these oscillations among brain regions has similarities with frequency division multiplexing (FDM) in telecommunications, which is used for multiplex transmission. If FDM-like information transmission...
Chapter
A simple model of learning that describes changes in an animal’s behavior based on its actions and rewards from the environment was analyzed by Karlin in 1953. The model can be formulated as an iterated function system with state-dependent probability. To develop a simple mathematical model of learning in which animals repeatedly alternate strategi...
Chapter
This study proposes self-organization of a second kind, by contrast with a conventional self-organization producing macroscopic patterns via cooperativity at the microscopic level of molecular dynamics. As a case study, we deal with two models yielding elementary components via global constraints controlling a whole system’s dynamics: one is the ge...
Chapter
The memory neural network is organized as an attractor space by both bottom-up (sensory) and top-down (contextual) information. This paper presents a possible mechanism of spatiotemporal attractors in one layer neural network based on the experimental data and their theoretical models in learning and memory. The model consists of following importan...
Chapter
We propose a neural mechanism of the concept of innate time, which may lead to a Kantian a priori time. The proposition is based on the assumption that Cantor coding and decoding associated with specific oscillatory behaviors in the hippocampus determines the ratio of internal compression of time intervals.
Chapter
Hippocampal-VTA microcircuit is one of the most important components of reward system. As a prominent feature in hippocampus, theta rhythm involves a strong correlation with learning, memory and decision making. However, the relation between theta rhythm and reward representation remains unclear. Based on some recent experimental discovery, a compu...
Chapter
From the viewpoint of system development, we investigate how components emerge in a network system consisting of interacting units. We propose two mathematical models with ‘variational’ principles: one treats the emergence of neuron-like components from interacting maps, and the other one treats the emergence of hierarchical module-like components...
Chapter
The aim of this study is, together with a companion paper, to present a hypothetical description of the core mechanisms of recurrent complex visual hallucinations (RCVH) associated with dementia with Lewy bodies (DLB). This paper focusses on giving some illustrative numerical examples on how the brain hallucinates, and to see whether mathematical m...
Chapter
Patients with dementia with Lewy bodies (DLB) frequently experience the phenomenon of visual hallucination (VH), which Collerton (2005) aptly described as “people see things that are not there.” The possible involvement of cholinergic deficiency in the VH seen in DLB have long been proposed, but the precise neural mechanism to account for the parti...
Article
By re-examining the neuronal activity energy model, we show the inadequacies in the current understanding of the energy consumption associated with neuron activity. Specifically, we show computationally that a neuron first absorbs and then consumes energy during firing action potential, and this result cannot be produced from any current neuron mod...
Article
The purpose of the research project entitled “The study on the neural dynamics for understanding communication in terms of complex hetero systems” was to establish a new research area named “neural information science for communication” by elucidating its neural mechanism. The research was performed in collaboration with applied mathematicians in c...
Article
Patients with dementia with Lewy bodies (DLB) frequently experience visual hallucination (VH), which has been aptly described as people seeing things that are not there. The distinctive character of VH in DLB necessitates a new theory of visual cognition. We have conducted a series of studies with the aim to understand the mechanism of this dysfunc...
Article
Chaotic itinerancy is an autonomously excited trajectory through high-dimensional state space of cortical neural activity that causes the appearance of a temporal sequence of quasi-attractors. A quasi-attractor is a local region of weakly convergent flows that represent ordered activity, yet connected to divergent flows representing disordered, cha...
Article
Full-text available
Modular architecture has been found in most cortical areas of mammalian brains, but little is known about its evolutionary origin. It has been proposed by several researchers that maximizing information transmission among subsystems can be used as a principle for understanding the development of complex brain networks. In this paper, we study how h...
Article
Full-text available
Motivated by studies on the dynamics of heterogeneously interacting systems in neocortical neural networks, we studied heterogeneously-coupled chaotic systems. We used information-theoretic measures to investigate directions of information flow in heterogeneously coupled Rössler systems, which we selected as a typical chaotic system. In bi-directio...
Article
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The brain contains multiple yet distinct systems involved in reward prediction. To understand the nature of these processes, we recorded single-unit activity from the lateral prefrontal cortex (LPFC) and the striatum in monkeys performing a reward inference task using an asymmetric reward schedule. We found that neurons both in the LPFC and in the...
Chapter
We propose a dynamical model that represents a process of deductive inference. We discuss the stability of logic dynamics and a neural basis for the dynamics. We propose a new concept of descriptive stability, thereby enabling a structure of stable descriptions of mathematical models concerning dynamic phenomena to be clarified. The present theory...
Article
A number of memory models have been proposed. These all have the basic structure that excitatory neurons are reciprocally connected by recurrent connections together with the connections with inhibitory neurons, which yields associative memory (i.e., pattern completion) and successive retrieval of memory. In most of the models, a simple mathematica...
Article
Full-text available
The medial frontal cortex has been thought to be crucially involved in temporal structuring of behavior in monkeys and humans. We examined neuronal activity in the supplementary and presupplementary motor areas of monkeys to investigate how the nervous system deals with the coding of 16 motor sequences resulting from multiple actions involving bila...
Article
We treated the interactions between two nonequilibrium neural networks, each of which possesses memories that are different from those of the other. In this respect, we developed a kind of hetero interaction that is a crucial ingredient for assuring communication.We propose a new learning algorithm for assuring different neural activity in both the...
Chapter
We present a mathematical model to describe interacting processes of model neural networks. A model consists of several subsystems, each of which describes each different function. An overall dynamics of the whole model stems from the interactions between different areas of the brain, influenced by the incoming dynamics of the other brains. In part...
Chapter
It has been proposed an abstract memory model of cortex that the recurrent network with inhibitory interneurons shows the successive retrieval of memories. It has not, however, been clarified whether such behavior appears in the realistic network model with the Hodgkin-Huxley type of neuron. By using the realistic model that consists of excitatory...
Chapter
There is evidence of presynaptic modulation of inhibitions on pyramidal neurons in cortical layers 2/3, mediated by muscarinic M2-receptors activated by transient releases of the corticopetal acetylcholine associated with top-down attention. Little is known, however, regarding its system-level consequences and possible implications for cognitive fu...
Chapter
In this paper, a communicative model with two nonequilibrium neural networks is proposed to emulate the dynamical process of how we can understand each other. A novelty-induced learning process is introduced to realize memory transmission between heterogeneous neural network models. The simulation results suggest that the communicative model could...
Article
In this paper, we mathematically study a particular process for assimilation in the brain. The research aims to establish a theoretical model at computational level of the mechanism in a cognitive process operated by the mirror-neuron system, to generate a multi-dimensional system from this model, and to analyze the fundamentals of the related cogn...
Chapter
Because episodic memory includes a time series of events, an underlying dynamics for the formation of episodic memory is considered to employ a mechanism of encoding sequences of events. The “Cantor coding” hypothesis in hippocampal CA1 has been proposed, which provides a scheme for encoding temporal sequences of events. Here, in order for investig...
Chapter
The hippocampus has been considered responsible for the formation of episodic memory. It has also been pointed out that the hippocampus plays an important role in imagination, which is related to future events. The fact that atrophy of the hippocampus could lead to Alzheimer’s disease implies that the network structure of the hippocampus may provid...
Article
We studied heterogeneously‐coupled Rössler oscillators in order to understand dynamics of hetero‐interactions. By using an information‐theoretic measure called transfer entropy, the directions of information flows in hetero‐interacting systems were investigated. We found the asymmetry of information flow emerged in the mutually‐coupled systems. Fur...
Article
Although the role of corticopetal acetylcholine (ACh) in higher cognitive functions is increasingly recognized, the questions as (1) how ACh works in attention(s), memory dynamics and cortical state transitions, and also (2) why and how loss of ACh is involved in dysfunctions such as visual hallucinations in dementia with Lewy bodies and deficit of...
Article
In this paper, four spatiotemporal coding mechanisms in the CA3-CA1were examined.
Article
For the last few decades, extensive research has been continuing in neuroscience supported by great development of experimental techniques (fMRI, PET, EEG, ECoG, EMG, Optical Recording, etc.) and/or computer experiment technologies. In a large number of works, many applied mathematical or physical approaches have been proposed, in particular, dynam...
Article
We study collective behaviors of diffusively coupled oscillators which exhibit out-of-phase synchrony for the case of weakly interacting two oscillators. In large populations of such oscillators interacting via one-dimensionally nearest neighbor couplings, there appear various collective behaviors depending on the coupling strength, regardless of t...
Article
Full-text available
Recent studies suggest that the hippocampus is crucial for memory of sequentially organized information. Cantor coding in hippocampal CA1 is theoretically hypothesized to provide a scheme for encoding temporal sequences of events. Here, in order to investigate this Cantor coding in detail, we construct a CA1 network model consisting of conductance-...
Chapter
Cortical layer 1 is the main entrance of top-down signals from other higher cortices and subcortical nuclei. Recent findings challenge the view that top-down signals play just a modulatory role. However, how top-down signals are implemented to help reconstruct the internal representations of images, or an episode of events is poorly understood. Rec...
Article
Cantor coding provides an information coding scheme for temporal sequences of events. In this paper, we analyzed a inhibitory network dependency in Cantor coding from hippocampal CA1 neurons of rat acute slice preparation by using GABAA receptor blocker (gabazine). After gabazine application, clustering index was lower under subthreshold condition...
Article
Full-text available
In this paper, we study a dynamic structure of discretized vector fields obtained from the Brusselator, which is described by two-dimensional ordinary differential equations (ODEs). We found that a bifurcation structure of the logistic map is embedded in the discretized vector field. The embedded bifurcation structure was unraveled by the dynamical...
Article
Full-text available
How does the information of spatiotemporal sequence stemming from the hippocampal CA3 area affect the postsynaptic membrane potentials of the hippocampal CA1 neurons? In a recent study, we observed hierarchical clusters of the distribution of membrane potentials of CA1 neurons, arranged according to the history of input sequences (Fukushima et al C...
Article
Full-text available
In contrast to the conventional static view of the brain, recent experimental data show that an alternative view is necessary for an appropriate interpretation of its function. Some selected problems concerning the cortical transitory dynamics are discussed. For the first time, we propose five scenarios for the appearance of chaotic itinerancy, whi...
Conference Paper
The following coding mechanisms in the CA3-CA1 hippocampal networks were examined. Firstly, the way in which the information of the spatio-temporal sequence of the hippocampal CA1 pyramidal cells was clarified by using the patch-clamp recording method. The input-output relations were analyzed by applying “spatial clustering index” and its “self-sim...
Conference Paper
In rat CA1 pyramidal neurons under sub- and supra-threshold conditions, our previous study showed the potentials of Cantor coding, which is theoretically proposed by Tsuda and Kuroda. However, the coding could be explained by mean rate coding simply depended on input pattern history of the peak amplitude of each input. In order to confirm that Cant...
Article
Full-text available
2008-32-0010 (SAE) / 20084710 (JSAE) We focus on the control issue for engine systems from the perspective of chaos theory, which is based on the fact that engine systems have a low-dimensional chaotic dynamics. Two approaches are discussed: controlling chaos and harnessing chaos, respectively. We apply Pyragas' chaos control method to an actual en...
Article
The hippocampus, which is a part of the old brain, has been considered responsible for the formation of episodic memory. Atrophy of the hippocampus can lead to Alzheimer disease. Alzheimer disease is a problem of the society. It is also expected to pose a serious problem in future societies composed of large numbers of elderly people. Therefore, it...
Article
To adapt to changeable or unfamiliar environments, it is important that animals develop strategies for goal-directed behaviors that meet the new challenges. We used a sequential paired-association task with asymmetric reward schedule to investigate how prefrontal neurons integrate multiple already-acquired associations to predict reward. Two types...
Article
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I would like to deal with a process that numbers are generated by the interaction between consciousness and memory, associated with time with a finite width. It is pointed out that this process can be related with the emergence of preafference. It is concluded that only humans can create numbers, whereas animals simply produce 'random' sequences of...
Article
Full-text available
How does the brain encode episode? Based on the fact that the hippocampus is responsible for the formation of episodic memory, we have proposed a mathematical model for the hippocampus. Because episodic memory includes a time series of events, an underlying dynamics for the formation of episodic memory is considered to employ an association of memo...
Chapter
The Role(s) of corticopetal acetylcholine (ACh) in perception and conscious flow is largely unknown. The attention hypothesis may well be established experimentally. The aim of this talk is to give a small review, and then try to extend further the arguments, on the role of corticopetal ACh in perception from a dynamical systems standpoint, to sear...
Article
Full-text available
To clarify how the information of spatiotemporal sequence of the hippocampal CA3 affects the postsynaptic membrane potentials of single pyramidal cells in the hippocampal CA1, the spatio-temporal stimuli was delivered to Schaffer collaterals of the CA3 through a pair of electrodes and the post-synaptic membrane potentials were recorded using the pa...
Article
In rat CA1 pyramidal neurons, our previous study showed Cantor coding like property, which is theoretically proposed by Tsuda and Kuroda. In this study, we analyzed the clustering properties by one and two steps before the sequences of electrical stimulation in CA1 pyramidal neurons after many action potentials. The membrane responses after action...
Conference Paper
A new hypothesis on a possible role for the corticopetal acetylcholine (ACh) is provided from a dynamical systems standpoint. The corticopetal ACh helps to transiently organize a global (inter- and intra-cortical) quasi-attractors via gamma range synchrony when it is behaviorally needed as top-down attentions and expectation.
Article
Full-text available
We analyze a time series of the combustion pressure in the idle state, measured from a spark ignition engine of a motorcycle. It is clarified that the engine system can be described by a lowdimensional deterministic dynamics perturbed by some stochastic process.We also propose a method to stabilize the chaotic behaviour of engine’s data by adopting...
Article
We review basic concepts of dynamical systems in the first half of this article. In the second half, we focus on cortical transitory dynamic behaviors observed during task-related actions of animals, and provide a dynamical interpretation of such transitory behaviors in terms of chaotic itinerancy.
Article
We propose a framework of neurocognitive experiments that clarifies structures of descriptions for the observed data. This framework can be used to determine the limitation of their possible interpretations and to reveal tacit assumptions of the experiments. We apply the f