Rhythms generation in a population of neurons simulated by a neural mass model

An original simple neural mass model of a population of neurons has been used to investigate the origin of EEG rhythms. The model consists of four neural subgroups connected to each other (pyramidal cells, excitatory interneurons, GABA_slow interneurons, GABA_fast interneurons). The parameters of the model describing the connectivity among neural subgroups have been changed in order to reproduce different EEG rhythms. An accurate analysis on the parameters describing GABA_fast interneurons has been performed to assess the role of these cells in the generation of gamma (γ) activity. Moreover, two neural populations have been connected by using different typologies of long range connections. Results show that the model of a single population is able to simulate the occurrence of multiple power spectral density (PSD) peaks; in particular the loop including GABA_fast interneurons seems to have a critical role in the activation in γ band, as confirmed by in vivo studies. The model can be of value to gain a deeper insight into mechanisms involved in the generation of γ rhythms and to provide better understanding of cortical EEG spectra.