Figure 4
From: Transient and selective suppression of neural activity with infrared light
Nerve conduction block in the rat sciatic nerve.
(a) A monopolar cuff electrode stimulated propagating APs along the nerve trunk. A 400 μm diameter fiber optic coupled to a diode laser was positioned over the tibial branch. (b) A train of infrared pulses (λ = 1450 nm; τpo = 0.2 ms; indicated schematically by a gray bar) at 200 Hz reduces the amplitude of EMG recordings for MG and LG. Electrical artifacts are blanked for clarity. (c) Single EMG responses are shown before, during and after infrared inhibition. Each trace is 20 ms. (d) Average iEMG for MG and LG before, during and after laser exposure (** p < 0.01; N = 2 nerves; n = 12 trials). Because of differences in absolute magnitude between the nerves tested, iEMG were normalized to the average iEMG for 1 sec prior to infrared exposure. (e) Local temperature increased by approximately 9°C during the 3 second infrared exposure. The thermal relaxation time was approximately 0.75 sec. (f) Increasing duration of radiant exposure yielded greater reduction in the iEMG for LG. The location where reduction in iEMG for LG first becomes significant (p < 0.002) is indicated by an arrow in (f) and orange dashed lines in (e). Data are presented as mean ± SEM.
