Autapse-induced firing patterns transitions in the Morris-Lecar neuron model

In 1948, Hodgkin identified three firing patterns of a single neuron in response to increasing the external DC input. In this work, we investigated the responses of a single neuron with an autapse based on a modified Morris-Lecar neuron model, which can exhibit the three types of firing patterns by changing only one parameter. An excitatory autapse was found to enhance the firing frequency, but an inhibitory autapse suppressed neuron firing. With excitatory autaptic feedback, the firing of a Class-1 neuron could be switched to that of a Class-2 neuron, and a Class-3 neuron could exhibit a Class-2 firing pattern. The sustained response frequency of the Class-2 neuron transferred from that of Class-3 is only dependent on the autaptic time delay, and the frequency decays gradually with increased the delay time.