TISSUE REACTION TO ELECTRODES: THE PROBLEM OF SAFE AND EFFECTIVE STIMULATION OF NEURAL TISSUE

Electrical stimulation is an effective albeit an unnatural, means of exciting neurons and axons, and certain precautions are necessary if tissue injury is to be avoided. Prolonged electrical stimulation can inflict neural injury that is clearly evident in histologic sections, and also may induce more subtle (and usually reversible) changes, included prolonged depression of electrical excitability. This chapter reviews the electrochemistry of charge injection into tissue by metal stimulating electrodes and discusses several mechanisms by which the stimulation might induce neuronal injury, both in the central nervous system and in peripheral nerves.