FIG. 7.

Continuous-wave LiFU modulates action potential discharge rate and mimics low-frequency mechanical stimulation. Representative sustained-type saccular afferent neuron showing continuous modulation of action potential discharge rate in response to (A) continuous wave LiFU at 5.1 Hz (ISI⁻¹, red dots), (B) sinusoidal mechanical displacement at 5 Hz (ISI⁻¹, blue dots), and (C) combined stimuli with responses beating at the difference frequency of 0.1 Hz (ISI⁻¹, purple dots). The LiFU stimulus was stronger than the mechanical stimulus [(A) vs (B)], so a residual remained during destructive interference. (D) Stimulus phase histograms showing probability of evoking action potentials in response to 5.1 Hz continuous 5 MHz LiFU stimulus (red) and 5 Hz sinusoidal mechanical stimulus (blue).