A Method for Chronically Implanting Stimulating Electrodes into the Brains of Locusts, and Some Results of Stimulation

Abstract

Methods are described for implanting permanent stainless-steel electrodes into the brains of locusts, for stimulating the brain under near-normal conditions, and for localizing the electrode subsequently. Threshold currents measured under these conditions are lower than those required in acute preparations, or if the animal is restrained. The results of stimulation are described for four common aspects of behaviour. These are antennal movement, locomotion, feeding and sexual behaviour. The effect of stimulation on antennal and locomotory movements largely confirms previous work on crickets. Feeding and foraging behaviour, which is a very common result, is shown to be almost completely determined by peripheral stimuli at the time of brain stimulation. The role of the latter is permissive or disinhibitory rather than causal or excitatory. Integrated sexual behaviour is occasionally inhibited, but never elicited, by stimulation. This contrasts with observations on crickets, and its implications are discussed.