Resonance induced by mixed couplings in a three-node motif
- PDF / 688,878 Bytes
- 8 Pages / 547.087 x 737.008 pts Page_size
- 77 Downloads / 168 Views
ORIGINAL PAPER
Resonance induced by mixed couplings in a three-node motif Cong Liu · Xiyun Zhang · Xiaoming Liang
Received: 28 February 2020 / Accepted: 12 August 2020 © Springer Nature B.V. 2020
Abstract Inspired by the coexistence of excitatory and inhibitory neurons in real neural networks, we propose a motif of three coupled nodes, one with positive coupling and two with negative couplings, for signal amplification. Utilizing the bistable overdamped oscillator as well as the excitable neuron models, we show that the response of the motif is optimized for an intermediate range of coupling strength, i.e., couplinginduced resonance. Through theoretical analyses, we find that the underlying mechanism for the resonance is an abrupt pitchfork bifurcation caused by the mixed positive and negative couplings. Keywords Signal amplification · Bistable overdamped oscillator · Excitable neuron · Mixed couplings · Motif · Pitchfork bifurcation
1 Introduction Diverse animals possess particular sensory system that can efficiently detect and response to external signals, even when the signals are weak [1–3]. For example, a crayfish can sensor perturbations in the surrounding C. Liu · X. Liang (B) School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China e-mail: [email protected] X. Zhang Department of Physics, Jinan University, Guangzhou 510632, Guangdong, China
environment caused by nearby predators [4], and a fox can hear the footsteps of mice under the snow [5]. In order to understand these natural phenomena, as well as for relevant bionic applications, it has become an important field in neuroscience of understanding the origin of the ability for a sensory system to detect weak signals [6–10]. At the single neuron level, researchers have discovered that additional noise to an excitable neuron can improve the detectability to a faint signal under certain conditions. Such an noise-induced improvement may arise from the effect known as stochastic resonance (SR)—adding noise with suitable intensity makes a weak signal accessible for an excitable neuron [11– 13]. This additional noise may originate from environmental fluctuations or biochemical and electrical activities [7,14]. Notably, noise with neither strong nor small intensity can lead to stochastic resonance. For small additional noise, the weak signal cannot be raised enough to fire the sensory neuron, while too strong noise will overwhelm the signal which leads to random firings of the sensory neuron. In contrast, intermediate noise may trigger the sensory neuron to fire with a rhythm matching the period of the driving signal, which leads to an enhanced response. At the neuronal population level, the SR response of a single neuron can be further enhanced when coupled into an neuron array, which is known as array-enhanced SR [15–17]. However, in most natural systems, neurons are organized through complex networks whose structures are
123
C. Liu et al.
neither purely random nor regular [18–21]. It has been shown that the stru
Data Loading...