Models of neocortical neuronal networks and observed emergent phenomena

The cerebral cortex displays specific patterns of spontaneous activity produced endogenously. These states are characterized with respect to the degree of synchrony of the collective neuronal activity and the level of irregularity of action potential spikes of individual neurons. A problem posed to theoretical neuroscience is how to model the emergence of synchronous and asynchronous spontaneous states from the same network of spiking neurons. In this article, three models that offer solutions to this problem are reviewed. The models use spiking neurons of the class known as integrate-and-fire and consider different network structures and synaptic dynamics. Mechanisms adopted by the models, like balance between excitation and inhibition and spiking-dependent adaptation, are discussed and contextualized. In parallel, this article presents some concepts utilized in the modelling of neurons and synapses, offering a quick introduction to theoretical neuroscience.

Keywords
Neocortex; Spontaneous brain activity; Integrate-and-fire neurons; Spiking neural networks; Synchronized and desynchronized cortical states