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. Author manuscript; available in PMC: 2015 Oct 1.
Published in final edited form as: Curr Opin Neurobiol. 2014 Jul 5;0:42–47. doi: 10.1016/j.conb.2014.06.002

Figure 2. Vocal learning as a functional transform.

Figure 2

A–B quantitative examination of the input/output relationship with respect to syllable duration. A, sonograms of isolate song (top) and its imitation (bottom). Red bars outline an isolate syllable of long duration, and its shorter version in the imitation of that song by a juvenile zebra finch. B, a plot summarizing the imitation of isolate syllables with respect to syllable-duration across eight birds who imitated isolate songs. As shown, syllable durations are copied faithfully within an input range of up to about 270ms. Above this range, imitation is invariably shorter than the sensory input. C–D, frequency dependent imitation. C, sonogram of isolate song showing a rare syllable type (A) and an abundant syllable type (B). In the imitation of this song, the rare syllable becomes more abundant and the abundant syllable becomes more rare (note also that its spectral features are not accurately copied). D, a plot, same as in B, but for relative frequency (abundance). Note that the imitation of relative frequency is faithful in the range of 10–25%, but for higher abundance, the imitation asymptotes on about 25%. Altered from Feher et al. [41]