A new method for automatic registration of stereotyped behaviour in the rat

A new and sensitive method for registering stereotyped behaviour in the bucco-oral region of the rat is described. These stereotypies, which can be induced by amphetamines and apomorphine, are regarded as an expression of the activation of dopaminergic receptors within the nigro-neostriatal pathway. The method is based on the fact that it is particularly easy in animals placed in restraining cages to induce stereotyped chewing, licking and gnawing movements which are received by special pick-ups in the head region of the animals and registered automatically and continuously via electro-mechanical transformers or by direct measurement of the change in the electrical resistance of the system. With this well-reproducible procedure it is possible to recognize and quantify the stereotypy-inducing effect of amphetamines and apomorphine and the influence of neuroleptic agents and tricyclic antidepressants on this effect. In comparison to previously described procedures, this method has the advantage of not being dependent on observation of the animals and of being highly suitable for the demostration of dose-effect and time-effect relationships.