Activation of pain pathways in animals.

In analyzing the anatomy and physiology of sensory systems it is often necessary that one activate the particular system being studied with appropriate stimulation. In experiments where this is necessary, the stimulation presented should be specific to the sensory system under study. With the pain system, however, this is most difficult since most stimuli that activate pain pathways also activate other pathways such as those that mediate touch and pressure sensations. It is also helpful to have available a stimulation technique that can be used in both acute experiments and long term neurophysiological and behavioral experiments. For investigation of the anatomical substrates of pain perception, a technique has been developed for implantation of bipolar electrodes in the teeth of cats that permits one to stimulate the tooth pulp in acute or chronic preparations, and, thus, to activate a pain pathway exclusively and directly. This technique provides a stimulus that is readily quantifiable, easily controlled, entirely nociceptive in character, and which can be used in a wide variety of situations.