Mechanisms of Self-Sustained Oscillatory States in Hierarchical Modular Networks with Mixtures of Electrophysiological Cell Types.

Petar Tomov,Michael A Zaks,Antonio C Roque,Rodrigo F O Pena

doi:10.3389/fncom.2016.00023

Abstract

In a network with a mixture of different electrophysiological types of neurons linked by excitatory and inhibitory connections, temporal evolution leads through repeated epochs of intensive global activity separated by intervals with low activity level. This behavior mimics “up” and “down” states, experimentally observed in cortical tissues in absence of external stimuli. We interpret global dynamical features in terms of individual dynamics of the neurons. In particular, we observe that the crucial role both in interruption and in resumption of global activity is played by distributions of the membrane recovery variable within the network. We also demonstrate that the behavior of neurons is more influenced by their presynaptic environment in the network than by their formal types, assigned in accordance with their response to constant current.

Highlights

Networks of cortical neurons display sustained activity even in the absence of external input
The process abruptly ended with complete termination of activity: the system found itself at the stable state of rest
We conjectured that the observed oscillatory sustained activity (SSA) states were transiently chaotic: that in the phase space of the system there was a non-attracting chaotic invariant set of zero measure, and that the generic trajectories did not stay in the vicinity of that set forever, but, after a shorter or longer motion along it, left it for the state of rest

Summary

Introduction

Networks of cortical neurons display sustained activity even in the absence of external input. Evidence of this self-sustained activity (SSA) comes from in vitro preparations of cortical tissue slices (Sanchez-Vives and McCormick, 2000; Mao et al, 2001; Cossart et al, 2003; Shu et al, 2003) or cell cultures (Plenz and Aertsen, 1996; Wagenaar et al, 2006), and in vivo cortical “slab” preparations (Burns and Webb, 1979; Timofeev et al, 2000; Lemieux et al, 2014). During near quiescent network activity single neurons have hyperpolarized membrane potentials close to resting state (down state)

Methods

Results

Conclusion