A simple device to measure stereotyped rearing of the rat in an objective and quantitative way

An inexpensive and simple device is described which measures stereotyped rearing of the rat automatically. The apparatus works on the principle of capacitance changes of an oscillator system, these changes being caused by postural changes, in this case by the rearing of the animal. Whenever the rat is standing on the hind feet with the head over a constant, but deliberately adjustable level, the change in capacitance starts a digital counter which measures and totalizes the time spent in this position with a freely-chosen accuracy (0.1 sec in the present case). The efficiency of the method has been checked by measuring the stereotypy caused by various doses of intraperitoneal apomorphine and the dose-related inhibition of this effect by bilateral intracaudate pretreatment with triperidol.