FIGURE 1.
Experimental setup. (A) Simplified pyloric circuit. The pyloric network consists of 14 neurons, which can be grouped as follows: the anterior burster neuron (AB), two pyloric dilator neurons (PD), eight pyloric neurons (PY), and one lateral pyloric neuron (LP). (B) A schematic representation of the dynamic clamp experiment. A pharmacologically isolated AB/PD complex was impaled with conventional sharp microelectrodes via a single PD neuron, and the membrane potential (V) recorded from the PD neuron is used to determine how much synaptic current (Isyn) this neuron receives through the artificial synapse. (C) Phase resetting in a biological neuron. The membrane potential record from a free running AB/PD complex, with an intrinsic period P0, is perturbed at the stimulus interval ts by an inhibitory synaptic input with gmodel1>bio1 = 100 nS and a duration of 500 ms. An upward crossing of the voltage threshold (horizontal dashed line at −45 mV) is defined as the beginning of the burst and assigned a phase of zero. As a result of this particular perturbation, the first burst after the perturbation is advanced such that P1 < P0. The length of the second cycle is P2 ≅ P0, which implies that the second order resetting in this case is negligible. (D) Phase resetting in a model neuron. In this example, a strong inhibitory perturbation with gbio1>model1 = 100 nS and a burst duration of 500 mS, applied during the burst of model neuron 1, terminates the ongoing burst. The length of the perturbed cycle P1 is not significantly altered, but the burst length (b1) in the cycle that contains the perturbation is shortened, as is the length of the cycle after the perturbation and the burst (b2) in that cycle. The burst threshold for this model neuron was −42 mV (horizontal dashed line).