Emergência de flutuações de atividade em modelos de redes corticais com populações neurais heterogêneas

Abstract

Most theoretical studies of cortical network dynamics have concentrated on networks with non-modular architecture and homogeneous neuronal composition, usually described by unstructured networks with Erdős-Rényi topology (Erdős & Rényi, 1959) populated by leaky integrate-and-fire neurons (Gerstner, Kistler, Naud, & Paninski, 2014). The main contribution of this thesis was to extend these studies to networks with a more elaborate architecture, namely hierarchical modular, which captures elements of the organization of the cortical brain network (Meunier, Lambiotte, & Bullmore, 2010), composed of heterogeneous neuronal populations with distinct firing patterns, modeled by two-dimensional integrate-and-fire neurons (Gerstner et al., 2014). The network models studied here exhibit a rich repertoire of dynamic activity patterns, and this thesis describes, analyses and explains the underlying mechanisms of some of these patterns for the first time. 1.4 Organization of the thesis The structure of this thesis was inspired on the "traditional complex" arrangement (Paltridge, 2002), where general introduction and methods are followed by studies presented in different chapters with their own introduction, methods, results, and discussion sections. In the end, general conclusions are presented. A summary of the internal structure of each chapter follows: • In Chapter 2, we review the background and literature. We go through basic neuroscience modeling justifying the use of simplified models as the ones we will employ here. We introduce the reader to basic notions of phase-plane analysis which will be useful for the questions addressed in this thesis. • In Chapter 3 we present our general methods. There, we explain all the statistical measures used along the thesis. Although the common measures are placed here, in each chapter we also include a more specific methods section. • In Chapter 4, the first chapter with results, we investigate mechanisms behind the transient oscillatory activity observed in the models. Many of these results 1.5-Scientific publications derived from this thesis 1.5-Scientific publications derived from this thesis * j