Infrared neurostimulation in ex-vivo rat sciatic nerve using 1470 nm wavelength

Abstract Objective. To design and implement a setup for ex-vivo optical stimulation exploring the effect of several key parameters (optical power pulse duration), activation features (threshold, spatial selectivity) recovery characteristics (repeated stimuli) in peripheral nerves. Approach. A nerve chamber allowing electrical was designed built. 1470 nm light source chosen to stimulate nerve. photodiode module implemented synchronization channels. Main results . Compound neural action potentials (CNAPs) were successfully generated with infrared pulses 200–2000 µ s duration range 3–10 W. These determine radiant exposure 1.59–4.78 J cm ?2 Recruitment curves obtained by increasing durations at constant level. Neural threshold is reached mean 3.16 ± 0.68 energy 3.79 0.72 mJ. Repetition rates 2–10 Hz have been explored. In eight out ten sciatic nerves (SNs), repeated stimuli induced sensitization that CNAP amplitude progressively grows, representing an number recruited fibres. two SNs, CNAPs composed succession peaks corresponding different conduction velocities. Significance. The reported could shed on mechanism underlying neurostimulation. Our suggest that, sharp contrast stimuli, recruit slow fibres early on. This more physiological order recruitment opens perspective specific neuromodulation fibre population who remained poorly accessible until now. Short high-power wavelengths below 1.5 m offer interesting perspectives