Abstract
It has been demonstrated that spiral ganglion cells in the cochlea can be stimulated with infrared radiation (IR). The
potential benefits of infrared neural stimulation (INS) include the possibility of stimulating the neurons without direct
physical contact between the stimulation source and the neural tissue and the improved spatial selectivity. In order to
determine how INS can be best incorporated in both research and in neural interfaces, it is critical to identify the optimal
stimulation parameters for the laser. This study focuses on direct comparison of amplitudes of neural responses evoked
by various IR pulse shapes and durations. With the present experiments, the results indicate that the peak power is an
important variable for stimulating auditory neurons. While the radiant energy has little effect on amplitudes of
compound potentials (CAP) evoked by infrared pulses shorter than 70 s, it impacts the amplitudes for pulses 80 s and
longer. In addition, we show that the shape of the infrared pulse is important and varying the shape may allow an
expansion of response dynamic range while stimulating neurons. The results indicate that square pulses were the most
effective pulse shape to evoke CAPs.
