893 research outputs found

    Mammalian Brain As a Network of Networks

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    Acknowledgements AZ, SG and AL acknowledge support from the Russian Science Foundation (16-12-00077). Authors thank T. Kuznetsova for Fig. 6.Peer reviewedPublisher PD

    NASA JSC neural network survey results

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    A survey of Artificial Neural Systems in support of NASA's (Johnson Space Center) Automatic Perception for Mission Planning and Flight Control Research Program was conducted. Several of the world's leading researchers contributed papers containing their most recent results on artificial neural systems. These papers were broken into categories and descriptive accounts of the results make up a large part of this report. Also included is material on sources of information on artificial neural systems such as books, technical reports, software tools, etc

    Dynamical Analysis for High-Order Delayed Hopfield Neural Networks with Impulses

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    The global exponential stability and uniform stability of the equilibrium point for high-order delayed Hopfield neural networks with impulses are studied. By utilizing Lyapunov functional method, the quality of negative definite matrix, and the linear matrix inequality approach, some new stability criteria for such system are derived. The results are related to the size of delays and impulses. Two examples are also given to illustrate the effectiveness of our results

    Dynamical Analysis of DTNN with Impulsive Effect

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    We present dynamical analysis of discrete-time delayed neural networks with impulsive effect. Under impulsive effect, we derive some new criteria for the invariance and attractivity of discretetime neural networks by using decomposition approach and delay difference inequalities. Our results improve or extend the existing ones

    New Results for Periodic Solution of High-Order BAM Neural Networks with Continuously Distributed Delays and Impulses

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    By M-matrix theory, inequality techniques, and Lyapunov functional method, certain sufficient conditions are obtained to ensure the existence, uniqueness, and global exponential stability of periodic solution for a new type of high-order BAM neural networks with continuously distributed delays and impulses. These novel conditions extend and improve some previously known results in the literature. Finally, an illustrative example and its numerical simulation are given to show the feasibility and correctness of the derived criteria

    Phase models and clustering in networks of oscillators with delayed coupling

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    We consider a general model for a network of oscillators with time delayed, circulant coupling. We use the theory of weakly coupled oscillators to reduce the system of delay differential equations to a phase model where the time delay enters as a phase shift. We use the phase model to study the existence and stability of cluster solutions. Cluster solutions are phase locked solutions where the oscillators separate into groups. Oscillators within a group are synchronized while those in different groups are phase-locked. We give model independent existence and stability results for symmetric cluster solutions. We show that the presence of the time delay can lead to the coexistence of multiple stable clustering solutions. We apply our analytical results to a network of Morris Lecar neurons and compare these results with numerical continuation and simulation studies

    Space, time and memory in the medial temporal lobe

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    This thesis focuses on memory and the representation of space in the medial temporal lobe, their interaction and their temporal structure. Chapter 1 briefly introduces the topic, with emphasis on the open questions that the subsequent chapters aim to address. Chapter 2 is dedicated to the issue of spatial memory in the medial entorhinal cortex. It investigates the possibility to store multiple independent maps in a recurrent network of grid cells, from a theoretical perspective. This work was conducted in collaboration with Remi Monasson, Alexis Dubreuil and Sophie Rosay and is published in (Spalla et al. 2019). Chapter 3 focuses on the problem of the dynamical update of the representation of space during navigation. It presents the results of the analysis of electrophysiological data, previously collected by Charlotte Boccara (Boccara et al., 2010), investigating the encoding of self-movement signals (speed and angular velocity of the head) in the parahippocampal region of rats. Chapter 4 addresses the problem of the temporal dynamics of memory retrieval, again from a computational point of view. A continuous attractor network model is presented, endowed with a mechanism that makes it able to retrieve continuous temporal sequences. The dynamical behaviour of the system is investigated with analytical calculations and numerical simulations, and the storage capacity for dynamical memories is computed. Finally, chapter 4 discusses the meaning and the scope of the results presented, and highlights possible future directions
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