Electrochemistry in Action-Engineering the Neuronal Response to Electrical Microstimulation

Brain neuromodulation has revolutionized the medical treatment of neurological diseases and injuries; however, existing therapies are limited in their clinical scope of application. Most existing therapies are delivered through implanted macroelectrodes that reside either on top of or directly inside the brain. Estimates of the effective electric field spread from these devices generally span from thousands to millions of individual neurons. Unfortunately, some neurological diseases and injuries require stimulation fields of higher precision. Next-generation microneuromodulation devices (˜102 – 103 μm2 surface area) have been developed with hundreds of closely spaced channels. These devices may be able to provide electrical microstimulation in the form of biphasic, charge-balanced small amplitude square waves that provide salient, behaviorally relevant information to human subjects. However, there is a lack of knowledge incorporated into their safety and clinical use. Neuromodulation is a field of science, medicine, and bioengineering that encompasses implantable and non-implantable technologies, electrical or chemical, that act upon neural interfaces to improve life for humanity. Our research groups collaboratively investigate neuromodulation performed via electrical microstimulation. Our primary development target is brain neuromodulation. In this article we highlight the application of electrochemistry to the field of neuromodulation.