Auditory Memories and Feedback Processing for Vocal Learning

ANA AMADOR AND DANIEL MARGOLIASH

The Auditory Cortex

Springer

Lugar: New York; Año: 2011; p. 561 - 575

Vocal learning can be defined as the ability to acquire new vocalizations or modify the spectral or temporal structure of existing vocalizations based on environmental cues.  This definition can admit a rich set of non-auditory cues that may influence the vocal learning process, but here we focus on processing of auditory cues that are memorized and then drive changes in motor patterns. Vocal learning is distinct from auditory perceptual learning because only the former is associated with a change in vocal output. Nevertheless, vocal learning requires specific forms of auditory perceptual learning, typically related to auditory processing of species-specific vocalizations. At the same time, animals exhibit numerous behaviors related to species-specific perceptual processing that do not involve changes in the structure of vocal output, and structures in the brain that may participate in auditory perceptual learning may also participate in vocal learning. Thus the choice as to which forms of auditory perceptual learning to include in a discussion of vocal learning is imprecise and rather artificial.  Within mammals beyond humans, vocal learning is well established by extensive behavioral observations of geographic variation and cultural evolution – if not by the gold standards of isolation rearing and feedback modification – in cetaceans and some species of bats. Little is known about vocal learning pathways in mammals outside of humans.  In general, the diversity of the pathways and mechanisms, including forebrain auditory regulation, involved in the various lineages in which vocal learning arises remains unresolved.  This problem is now being approached in the birds, but remains poorly developed in studies of mammalian species.  This remains a major challenge in producing an integrated picture of the auditory mechanisms of vocal learning that spans the vertebrates. In the spirit of this volume, we attempt to provide a thematic organization identifying similar limitations of our knowledge and posing questions for future studies throughout this chapter.