Coupling a model neuron to a rhythmic biological circuit with the dynamic clamp
We use the dynamic clamp to add a model neuron to the pyloric pattern generator circuit in the stomatogastric ganglion of the lobster. The model neuron spikes tonically if isolated and fires bursts of action potentials if connected to one of the rhythmically active neurons in the circuit via mutually inhibitory dynamic clamp synapses, thus forming a hybrid half-center oscillator with a biological and a model neuron component. With a suitable choice of synapse strengths and dynamics, the additional neuron slows down the pyloric rhythm. The biological part of the hybrid circuit reacts to this perturbation by increasing its pyloric frequency on the timescale of hours, and this activity-dependent effect reverses after the model neuron is disconnected from the circuit.
By varying the synaptic connections between the model neuron and the pyloric circuit, we study the nature of the pyloric circuit's activity-dependent changes.