Abstract

Large and small cortexes of the brain are known to contain vast amounts of neurons that interact with one another. They thus form a continuum of active neural networks whose dynamics are yet to be fully understood. One way to model these activities is to use dynamic neural fields which are mathematical models that approximately describe the behavior of these congregations of neurons. These models have been used in neuroinformatics, neuroscience, robotics, and network analysis to understand not only brain functions or brain diseases, but also learning and brain plasticity. In their theoretical forms, they are given as ordinary or partial differential equations with or without diffusion. Many of their mathematical properties are still under-studied. In this paper, we propose to analyze discrete versions dynamic neural fields based on nearly exact discretization schemes techniques. In particular, we will discuss conditions for the stability of nontrivial solutions of these models, based on various types of kernels and corresponding parameters. Monte Carlo simulations are given for illustration.

Highlights

  • To model a large amount of cells randomly placed together with a uniform volume density and capable of supporting various simple forms of activity, including plane waves, spherical and circular waves, and vortex effects, Beurle (1956) proposed a continuous model consisting of a partial differential equation, that can capture some neurons behaviors like excitability at the cortical level. Amari (1977) and Wilson and Cowan (1972) subsequent modifications did allow for new features such as inhibition

  • We have proposed a discrete model for dynamical neural fields

  • We have proposed another proof of the existence of nontrivial solutions for dynamic neural fields

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Summary

INTRODUCTION

To model a large amount of cells randomly placed together with a uniform volume density and capable of supporting various simple forms of activity, including plane waves, spherical and circular waves, and vortex effects, Beurle (1956) proposed a continuous model consisting of a partial differential equation, that can capture some neurons behaviors like excitability at the cortical level. Amari (1977) and Wilson and Cowan (1972) subsequent modifications did allow for new features such as inhibition. Sk(xk, t) represents the intensity of the external stimulus at time t arriving on the neuron at position xk on the kth layer, see Figure 1 below. The remainder of the paper is organized as follows: in section 2, we propose our nearly exact discretization scheme for DNFs. In section 3.1, we make a brief overview of the essential notions for the stability analysis of discrete dynamical systems, in section 3.2, we discuss the existence on nontrivial fixed solutions for DDNFs, in sections 3.3 and 3.4, we discuss stability analysis for a one and multiple layers discrete DNFs. In section 3.5, we propose simulations and their interpretation for neural activity and, we make our concluding remarks

Discrete Schemes for DNFs
Pulse Emission Rate Functions
Connection Intensity Functions
Stability Analysis
Existence of Nontrivial Fixed Solutions for the DDNFs Model
Stability Analysis of Hyperbolic Fixed Solutions
Special Case of Single Layer Model With a Heaviside Pulse Emission Function
Multiple-Layers DDNFs Model
Special Case
Simulations
Single-Layer With Sigmoid Function With
DISCUSSION
DATA AVAILABILITY STATEMENT
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