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. 2015 Feb 18;35(7):2885–2894. doi: 10.1523/JNEUROSCI.3715-14.2015

Figure 2.

Figure 2.

FoxP2 overexpression during the sensorimotor critical period disrupts vocal learning. a, Spectrograms (frequency range of 0–11 kHz) depict motifs from a tutor and his three pupils which each received a stereotaxic injection of AAV1 driving either GFP expression (GFP) or FoxP2 (FoxP2+). Scale bars, 200 ms. Syllables that correspond across motifs are underlined with black bars and identified by letters (question marks indicate unidentifiable syllables). b, Quantification of the similarity of each pupil's motif to its tutor reveals that FoxP2+ birds (gray bars) have lower scores than those of GFP birds (green bars; p = 0.0269, n = 8GFP/10FoxP2+, unpaired one-tailed bootstrap). Midline represents mean, upper and lower bounds of the box represent SE, upper and lower whiskers represent 95% confidence intervals, and points represent individual birds. c, Manual counting of syllables revealed that FoxP2 overexpression leads to an increase in the number of tutor syllables that were omitted by the pupil (p = 0.0247, n = 8GFP/10FoxP2+, unpaired one-tailed bootstrap). In contrast, GFP and FoxP2+ pupils exhibit similar levels of improvised syllables (p = 0.3040, n = 8GFP/10FoxP2+, unpaired one-tailed bootstrap). d, The motifs of GFP and FoxP2+ pupils exhibit similar levels of syntax similarity to their tutor's motif (p = 0.2276, n = 7GFP/8FoxP2+, unpaired one-tailed bootstrap). e, Exemplar spectrograms of a different tutor and his three pupils (1 GFP, 2 FoxP2+) highlight the low fidelity imitation of tutor syllables by FoxP2+ pupils. f, Poor syllable imitation by FoxP2+ relative to GFP pupils is reflected in lower-syllable identity scores (p = 0.0067, n = 8GFP/10FoxP2+, unpaired one-tailed bootstrap). g, Syllable-by-syllable comparison of the feature-specific errors made by FoxP2+ pupils versus their GFP sibling. Black points above unity represent syllables for which the FoxP2+ sibling made larger errors, whereas green points below unity represent syllables for which the GFP sibling made larger errors. FoxP2+ pupils made larger errors for duration (100-sequential match), FM entropy, and goodness, but not pitch nor AM (p = 0.0115, 0.0004, 0.0239, 0.0108, 0.1196, 0.0761, respectively; n = 41 syllables, paired one-tailed bootstrap).