Neural mechanisms of birdsong memory.

The process through which young male songbirds learn the characteristics of the songs of an adult male of their own species has strong similarities with speech acquisition in human infants. Both involve two phases: a period of auditory memorization followed by a period during which the individual develops its own vocalizations. The avian 'song system', a network of brain nuclei, is the probable neural substrate for the second phase of sensorimotor learning. By contrast, the neural representation of song memory acquired in the first phase is localized outside the song system, in different regions of the avian equivalent of the human auditory association cortex.