Stimulation of neurons with infrared radiation

The goal for all neuroprostheses is to restore neural function to a condition having the fidelity of a healthy system. However, contemporary neural prostheses are not able to fully achieve this goal. These devices all use electrical current to stimulate the neurons. As determined by the electrode configuration and the electrical tissue properties, the current spreads in the tissue and consequently does not allow precise stimulation of focused neuronal populations, which results in overlap of stimulation fields when neighboring electrode contacts are used. In this book chapter, we present and discuss how photons can be used to overcome some limitations of electrical stimulation. In particular, the content of this text is focused on infrared neural stimulation (INS). Using INS for neural prostheses has its appeal. Many steps are required between technological conception and maturity of an INS-based prosthesis. The steps include biological safety, compatibility, and the engineering of a practicable device.