ABSTRACT
Transient optical stimulation of neural tissue is a fundamentally new approach to stimulate the peripheral nerve that has distinct advantages when compared to other peripheral nerve excitation modalities, including standard electrical nerve stimulation. This novel methodology for nerve excitation relies on irradiation of the nerve surface, in a noncontact fashion, with a pulsed (infrared) laser operating at an optimized radiant exposure and wavelength for the generation of compound action potentials and associated physiological effect (i.e., muscle contraction or sensory response). The response is extremely spatially precise, providing the possibility for selective targeting of individual nerve fascicles, and does not result in tissue damage at laser radiant exposures (energy/area) at least two times that required for a visible muscle contraction. Thus, optical stimulation presents an innovative contact-free approach to neural activation that may benefit clinical nerve stimulation as well as fundamental neurophysiology and neuroscience. This chapter defines and characterizes optical nerve stimulation as well as details the
methodology of this technique. The fundamental principles and experiments that help define the optimal parameters needed for safe and effective stimulation of the peripheral nerve are described. The biophysical mechanistic considerations and working hypotheses are briefly discussed. Finally, the potential impact of optical stimulation is noted in terms of applications and clinical utility for this technology.
