Gamma oscillations in a minimal CA3 model

A minimal model of the CA3 region of the hippocampus produces gamma oscillations. These oscillations exist across a broad range of conditions. For instance, the oscillations exist in the presence or absence of external input. Additionally, quantal synaptic failures do not eliminate the gamma oscillations. More importantly, there is a sensitivity to the average firing rates of neurons in the simulations. Specifically, increasing the average firing rates leads to a continuous phase transition that is a quenching of the gamma oscillations. Although the minimal model includes an inhibitory neuron, no explicit time constant of this neuron or the inhibitory synaptic conductance corresponds to the observed frequencies of oscillation.