Changes in excitatory/inhibitory balance affect network dynamics.
(A) Increasing the percentage of excitatory neurons in the network increased firing rate, oscillation frequency, and oscillation magnitude. In contrast, oscillation FWHM decreased with a higher proportion of excitatory neurons. All network parameters are normalized to the baseline (80% excitatory to 20% inhibitory) network. (B) The difference between average firing rate of neurons with the highest and lowest index values widened as the percentage of excitatory neurons increased. (C) As the percentage of excitatory neurons increased, the fraction of excitatory neuron spiking increased at oscillation peak and decreased at oscillation start and end, with most prominent changes occurring at the end of oscillations. With a lower percentage of excitatory neurons, opposite changes occurred with higher fractions of excitatory neuron spiking at the start and end of oscillations. As the proportion of excitatory neurons increased, the fraction of inhibitory neuron spiking decreased at start and increased at end of oscillation, with most prominent changes occurring at the start of oscillations. All spike fractions were normalized to the baseline (80% excitatory) network.