Parrots imitate song and dance with mixed vocal-gestural neural signals

Abstract

Humans shrug when saying "I don't know" and nod when saying "yes," yet it remains unclear how the brain coordinates vocal and gestural motor systems for learned, multimodal communication. Here we find that budgerigar parrots precisely imitate the fine temporal alignment between song and affiliative headbob gestures. Distinct colonies developed unique vocal-gestural motifs, which reorganized into new shared forms following social re-pairing. Neural recordings from the central nucleus of the anterior arcopallium (AAC), the cortical output of the parrot song system, revealed intermixed representations of vocalizations and head kinematics, including mixed selectivity at the level of single neurons. These findings show that socially learned multimodal communication is implemented by the joint representation of vocal and gestural motor signals within single neurons, revealing neural mechanisms that may extend to frontal cortical regions controlling speech and gesture in humans.