SWITCHING NEURONS ARE INTEGRAL MEMBERS OF MULTIPLE OSCILLATORY NETWORKS

Background: The stomatogastric ganglion of the crab Canter borealis co ntains the neurons that generate several different behaviors, such as the fast pyloric rhythm and the slower gastric-mill rhythm. It has pre viously been shown that many stomatogastric ganglion neurons can switc h between pyloric- and gastric-timed activity. However, the question r emained whether these neurons really are integral members of several c entral-pattern-generating networks, or just passive followers chat onl y change their activity patterns in response to a switch determined by other neurons. Results: To address this question, we perturbed the ac tivity of the 'pyloric' ventricular dilator neuron and the 'gastric' l ateral gastric neuron during ongoing pyloric and gastric rhythms. In t he absence of ongoing gastric rhythms, these neurons can fire in pylor ic time, and perturbing them can reset the pyloric rhythm. During robu st gastric activity, the lateral gastric and ventricular dilator neuro ns can fire in gastric time, and perturbing them can reset the gastric rhythm. Conclusions: When stomatogastric ganglion neurons change thei r firing patterns, they also function as part of the circuitry that ge nerates the new rhythm with which they are firing, demonstrating that individual neurons can be used as part of multiple pattern-generating circuits.