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Synchronization is deemed to play an important role in information processing in many neuronal systems. In this work, using a well known technique due to Pecora and Carroll, we investigate the existence of a synchronous state and the bifurcation diagram of a network of synaptically coupled neurons described by the Hindmarsh-Rose model. Through the analysis of the bifurcation diagram, the different dynamics of the possible synchronous states are evidenced. Furthermore, the influence of the topology on the synchronization properties of the network is shown through an example. Index Terms--Bifurcation, biological systems, networks, nonlinear oscillators, synchronization.

A spectral technique is proposed for investigating periodic oscillations and bifurcations in cellular nonlinear networks. The method consists of the following three fundamental steps: 1) an accurate estimation of the whole set of stable and unstable limit cycles is provided through the application of the describing function technique; 2) a detailed characterization of each limit cycle is obtained via the harmonic balance (HB) technique, by exploiting as input parameter the single harmonic approximation, provided by the describing function technique; 3) limit cycle stability and bifurcations are studied by computing the Floquet's multipliers and exploiting both a time-domain and an HB-based technique. Index Terms--Cellular nonlinear networks (CNNs), complex dynamics, nonlinear dynamic arrays, oscillations, spectral techniques.

Cellular neural networks (CNNs) are dynamical systems, described by a large set of coupled nonlinear differential equations. The equilibrium-point analysis is an important step for understanding the global dynamics and for providing design rules. We yield a set of sufficient conditions (and a simple algorithm for checking them) ensuring the existence of at least one stable equilibrium point. Such conditions give rise to simple constraints, that extend the class of CNNs, for which the existence of a stable equilibrium point is rigorously proved. In addition, they are suitable for design and easy to check, because they are directly expressed in term of the template elements. Index Terms--Cellular neural networks (CNNs), equilibrium analysis, nonlinear circuits, stable equilibrium points.