On the physiological and structural contributors to the dynamic balance of excitation and inhibition in local cortical networks .

Excitatory neurons largely dominate the microcircuitry of cortical networks and are central to their information processing endeavor. The recurrent excitation that they provide to each other allows the entire network to sustain its activity. Inhibitory neurons then play a crucial role in stabilizing and regulating this recurrent excitation. Otherwise, the recurrent excitation will lead to saturation of the excitatory activity. This dynamic self-regulated coordination of overall neuronal activity is a fundamental property of cortical networks. It results in an intrinsic balance of excitation and inhibition throughout a network, which sets the operating condition of the network's spontaneous activity at a highly excitable yet fully stabilized state.The importance of this excitation-inhibition balance to functionality of cortical networks has motivated numerous theoretical and experimental studies, aiming to understand how such a balance is established locally in cortical networks, and under what conditions it is disrupted. To further inform such studies, we use biologically plausible models of spontaneous neocortical activity to study how some of the key physiological and structural properties of local cortical networks contribute to establishing excitation-inhibition balance, and how this balance is dynamically affected by variations in those properties.