Activation using infrared light in a mammalian axon model.

Infrared neural stimulation (INS) offers the potential to selectively activate very small populations of neurons. Before it will be possible to design efficient and effective INS interfaces, the mechanisms of INS need to be better understood. The presented study builds on work indicating that INS generates a significant capacitive current by the application of infrared light to cell membranes. A computational model is presented to investigate realistic spatial delivery of INS and to investigate whether axonal structure and ion channel composition are likely to facilitate INS activation through capacitive changes alone. Findings indicate that capacitance changes are unlikely to be the sole mechanism, because the determined thresholds to activation were higher than the capacitance changes observed in previously reported work [1].