An electrode assembly for stimulation of a spinal cord within a spinal canal, the spinal canal containing a dura mater, the assembly incorporating a base, a lateral arm extending from the base； a ventral series of electrodes attached to base and to the lateral arm； a dorsal series of electrodes attached to the base and to the lateral arm； ventral and dorsal matrices of electrical conductors respectively communicating electrically with the ventral and dorsal series of electrodes； and an electric pulse generator for electrifying the ventral and dorsal conductors, the generator being adapted for exclusively electrifying the ventral matrix of electrical conductors, and for alternatively exclusively electrifying the dorsal matrix of electrical conductors.
