Background: The stomatogastric ganglion of the crab Cancer borealis contains the neurons that generate several different behaviors, such as the fast pyloric rhythm and the slower gastric-mill rhythm. It has previously been shown that many stomatogastric ganglion neurons can switch between pyloric- and gastric-timed activity. However, the question remained whether these neurons really are integral members of several central-pattern-generating networks, or just passive followers that only change their activity patterns in response to a switch determined by other neurons.
Results: To address this question, we perturbed the activity of the 'pyloric' ventricular dilator neuron and the 'gastric' lateral gastric neuron during ongoing pyloric and gastric rhythms. In the absence of ongoing gastric rhythms, these neurons can fire in pyloric time, and perturbing them can reset the pyloric rhythm. During robust gastric activity, the lateral gastric and ventricular dilator neurons can fire in gastric time, and perturbing them can reset the gastric rhythm.
Conclusions: When stomatogastric ganglion neurons change their firing patterns, they also function as part of the circuitry that generates the new rhythm with which they are firing, demonstrating that individual neurons can be used as part of multiple pattern-generating circuits.