Fig. 2.

Frequency specificity of two-tone suppression. The two components of the stimulus had here the same amplitude F₁ = F₂ = 2 pN. The frequency f₁ = 24 Hz of the test tone was fixed near the bundle’s characteristic frequency of oscillation f_C = 23 Hz, while the frequency f₂ of the masker tone was varied. The magnitude of bundle motion, at frequencies f₁ (●) and f₂ (○), is plotted as a function of the frequency separation Δf = f₂ - f₁. The dashed line represents the response level when the test tone was presented alone.