The frontal ganglion (FG) is part of the insect
stomatogastric nervous system and is found in most insect
orders. Previous work has shown that in the desert locust,
Schistocerca gregaria, the FG constitutes a major source of
innervation to the foregut. In an in vitro preparation,
isolated from all descending and sensory inputs, the FG
spontaneously generated rhythmic multi-unit bursts of
action potentials that could be recorded from all its
efferent nerves. The consistent endogenous FG rhythmic
pattern indicates the presence of a central pattern
generator network. We found the appearance of in vitro
rhythmic activity to be strongly correlated with the
physiological state of the donor locust. A robust pattern
emerged only after a period of saline superfusion, if the
locust had a very full foregut and crop, or if the animal
was close to ecdysis. Accordingly, haemolymph collected
at these stages inhibited an ongoing rhythmic pattern
when applied onto the ganglion. We present this novel
central pattern generating system as a basis for future
work on the neural network characterisation and its role
in generating and controlling behaviour