1. A method for restoring or improving nervous system function of a subject, said method comprising: providing an operant conditioning protocol effective to produce targeted neural plasticity (TNP) in a primary targeted central nervous system (CNS) pathway of a subject; and administering the operant conditioning protocol to the subject under conditions effective to elicit TNP in the primary targeted CNS pathway and to elicit generalized neural plasticity (GNP) in one or more other CNS pathways, wherein the elicitation of the GNP in the one or more other CNS pathway serves to restore or improve a nervous system function of the subject, and wherein the operant conditioning protocol is administered to the subject using a device for restoring or improving nervous system function, said device comprising: (i) a nerve stimulation-electromyographic recording component; and (ii) a controller for operating the nerve stimulation-electromyographic recording component in accordance with the operant conditioning protocol.