978-1-4577-2133-5/10/$26.00 ©2012 IEEE 165
2012 8th International Conference on Natural Computation (ICNC 2012)
Synchronization of FitzHugh-Nagumo Systems: An
Adaptive Approach
Wei Wei, Min Zuo, Zaiwen Liu
Department of Automatic Control, Computer and
Information Engineering School
Beijing Technology and Business University
Beijing, China
Jing Wang
National Engineering Research Center of Advanced
Rolling, University of Science and Technology Beijing,
China
Abstract—In this article, synchronization of FitzHugh-Nagumo
(FHN) neurons is considered. Adaptive controller based on active
compensation is adopted to drive the slave neuron to track the
master neuron. Sufficient condition for asymptotic stability of the
close-loop system is derived. Numerical simulation results are
given to confirm the adaptive controller is valid.
Keywords-synchronization; FHN neurons; adaptive
I. INTRODUCTION
Neurons play an important part in living beings’
information processing, therefore an increasing number of
researchers make efforts in understanding what is the dynamics
of the neurons and how the neurons interact each other.
Synchronization, a common phenomenon in natural world, was
also discovered in nervous system [1]. In addition, mammalian
nervous systems exhibit various synchronized behaviors [2].
Synchronization of the neurons is recognized as a crucial
mechanism in achieving critical functional goals including
biological information processing and the production of regular
rhythmical activity [3-5]. The synchronization of nervous
systems has become a focus of neurophysiology.
In order to analyze the synchronization in quantitative
approach, different kinds of nonlinear neural models have been
proposed, such as Hodgkin-Huxley (HH) model [6], FitzHugh-
Nagumo (FHN) model [7], Hindmarsh-Rose (HR) model [8],
Ghostburster neurons [9]. On the basis of those models,
nonlinear system theories are employed to analyze the
synchronization of the neurons. Various synchronization
approaches are presented to realize the synchronization [10-15].
H
∞
variable universe adaptive fuzzy control [10] is derived to
synchronize two FHN neurons. Nonlinear controller based on
the model of FHN is deduced to arrive at synchronization of
the coupled FHN systems [11]. Reference [12] proposed a
novel internal model control approach for the robust output
synchronization of FHN neurons under external electrical
stimulation. In the design process, synchronization problem is
converted into a stabilization problem of an augmented system
consisting of the original plant and internal model. High order
slide-mode control [13] and impulsive synchronization
approach [14] are utilized to synchronize HH and HR neurons
respectively. Additionally, the Ghostburster neurons’
synchronization problem is considered in [15] by H
∞
variable
universe fuzzy adaptive controller.
In this article, synchronization of FHN neurons is taken into
consideration. FHN neural model can be viewed as a simplified
version of HH model, which describes neuron dynamics and
the dynamics of excitable neurons under different external
electrical fields, such as kinematics of chemical reaction and
solid state physics [10]. References [10-12] have discussed the
synchronization of FHN neurons. As a matter of fact,
uncertainties do exist in real world, a synchronization approach,
which is easy and robust enough, is of great significance in
theory and practice. In this study, an adaptive controller based
on active compensation is adopted to synchronize the FHN
neurons under different external electrical stimulations.
Extended state observer included in the adaptive controller is
capable of estimating and compensating uncertainties in real
time, which guarantees good robustness of the closed-loop
system.
The rest of this article is organized as follows. Section II
describes the nonlinear dynamics of FHN neurons and the
synchronization problem. Section III gives out the
synchronization approach, numerical simulation results are
shown in Section IV, and conclusions are drawn in Section V.
II.
PROBLEM STATEMENT
A. Dynamics of FitzHugh-Nagumo Systems
The model of FHN neuron is described by
0
(1)(1 ) ()
xx rx y I t
ybx
=−−−+
⎧
⎨
=
⎩
(1)
where x and y are state variables. Membrane voltage V and
recovery variable W are rescaled by V
p
, the peak of the active
potential, respectively, i.e.
,
p
VW
xy
VV
==
. The variable r is
defined as
T
V
r
V
=
. V
T
denotes the threshold of the membrane
Supported by the Research Foundation for Youth Scholars of Beijing
Technology and Business University(QNJJ2011-40) and National Natural
Science Foundation of China(61170113).