Figure 6.

Targeted muscle stimulation drives significant changes in multiple acoustic parameters in singing birds. In the syllable and muscle shown in Figure 5b, a stimulating (Stim) current of 75 μA caused fundamental frequency (FF) to significantly increase (a; t₍₂₃₀₎ = 3.5, p < 0.01, two-tailed, two-sample t test), sound amplitude to significantly increase (b; t₍₂₃₀₎ = 3.9, p < 0.01, two-tailed, two-sample t test), and spectral entropy to significantly decrease (c; t₍₂₃₀₎ = 8.8, p < 0.01, two-tailed, two-sample t test). d, Perturbation of VS altered multiple acoustic parameters in 80% of cases (N = 5), while perturbation of DTB did so in 100% of cases (N = 6). *p < 0.05.