A series of the positive cord dorsum potentials (CDP)were recorded in the dorsal surface of the spinal cord when the region of the nucleus raphy magnus (NRM)was stimulated by electricity. This CDP (NRM—CDP) consisted of three potentials. They were a Compound potential with a short time course and two slow potentials with a long time course which followed the compound one. The characteristics of the slowly potentials—NRM—CDP—1 and NRM—CDP—2 waves were analysed the parameters concerned were recorded. Therefore, a good experiment animal model and new information are provided for the further a study of the NRM action.