Hemispheric differences in avian song discrimination.

Auditory input to the right or left forebrain of adult male zebra finches (Taeniopygia guttata) was disrupted by lesioning the ipsilateral auditory relay nucleus of the thalamus. These birds were then presented with two kinds of auditory discriminations: (i) between their own song and the song of a cage mate; (ii) between two versions of an unfamiliar zebra finch song that differed only in the harmonic profile of one of the syllables. Right-side lesion birds did better than left-side lesion ones at discriminating between their own song and the song of a cage mate; left-side lesion birds did better on the harmonic profile task. We suggest that the two halves of the zebra finch brain process conspecific sounds differently, as seems to be the case for humans.