Through a series of experimental study of auditory brain stem response (ABR) in rats under anesthesia, the authors have found the followings; 1) the most successful recordings of ABR in rats for a wide frequencies of sound could be obtained by placing the cathode at the forehead and the anode at the top of the head, 2) use of an ear mold and a sound collector helped to prevent the attenuation of the stimulating sound pressure, 3) being low in resistance, a silver ball electrode has been found to yield better results by reducing the artifact during the recording, 4) a conventional dose of the anesthetics, urethane chloralose, has been found not to produce umtoward effect on the recording but an excessive dose usually produced an elevation of the threshold of ABR.
