Networks of coupled circuits: From a versatile toggle switch to collective coherent behavior

TL;DR

This paper explores how networks of coupled circuits with feedback loops can act as toggle switches and exhibit collective behaviors like synchronization and transient patterns, with potential biological implications.

Contribution

It introduces a detailed bifurcation analysis of coupled feedback circuits, demonstrating control over switch states and collective oscillations, including spontaneous symmetry breaking.

Findings

Coupled circuits can function as toggle switches with controllable states.

Larger networks exhibit synchronized oscillations and transient pattern formation.

Self-organized pacemakers emerge dynamically in uniform ensembles.

Abstract

We study the versatile performance of networks of coupled circuits. Each of these circuits is composed of a positive and a negative feedback loop in a motif that is frequently found in genetic and neural networks. When two of these circuits are coupled with mutual repression, the system can function as a toggle switch. The variety of its states can be controlled by two parameters as we demonstrate by a detailed bifurcation analysis. In the bistable regimes switches between the coexisting attractors can be induced by noise. When we couple larger sets of these units, we numerically observe collective coherent modes of individual fixed-point and limit-cycle behavior. It is there the monotonic change of a single bifurcation parameter that allows to control the onset and arrest of the synchronized oscillations. This mechanism may play a role in biological applications, in particular in connection with the segmentation clock. While tuning the bifurcation parameter, also a variety of transient patterns emerges upon approaching the stationary states, in particular a self-organized pacemaker in a completely uniformly equipped ensemble, so that the symmetry breaking happens dynamically.