Figure 2. VoICE detects deafening-induced alterations in song phonology and syntax.

(a) Spectrograms reveal song deterioration in deafened, but not sham-deafened, birds. (b) Syllables are assigned in a temporally-reversed serial manner to account for ongoing changes in syllable structure. (c) Syllable entropy, a measure of spectral ‘noise’, increases in a majority of syllables after deafening. Asterisks denote statistically significant changes from before surgery (left). Bar plots represent Pre (Day 0) vs. Post* (the first day statistically significantly different from ‘Pre’) vs. Post (the last analyzed day) recordings. Each symbol and line (left) and its corresponding pair of bars (right) represent a syllable cluster (right). (One-way resampling ANOVA, multiple comparisons post-hoc Bonferroni corrected p-value < 0.05) (d) Syntax similarity to pre-surgery decreases following deafening. (Black = sham; blue, red = deaf, * = p < 0.05 resampling independent mean differences. Scale bars = 250 msec in a and b.)