Practice and sleep help birds learn new songs

London, Dec 15 (ANI): Researchers at the University of Chicago researchers have found that the reorganization of neural activity during sleep helps young songbirds to develop the vocal skills they display while awake.

It is known that sleep has a role in a broad range of learning processes studied in humans, but the neural mechanisms involved in the nighttime consolidation of learning are not well understood.

In order to study that, researchers used an animal model system, the developmental learning of song in songbirds, which long has been known to share features with learning speech and language.

In the study, Sylvan Shank, a recent Ph.D. graduate in Psychology, and Daniel Margoliash, Professor in Organismal Biology and Anatomy and in Psychology, found that when young zebra finches listen to an adult tutor's song and then practice singing, the activity of premotor neurons in the brain is altered during the following night's sleep.

The newly formed pattern of spikes in nighttime activity carries information both about the tutor song and auditory feedback the birds hear while singing.

These nighttime changes lead to improvements the young birds' singing that can be observed the following day.

"This study takes big steps forward in finding out how sleep impacts learning. We looked at juvenile birds at the first moments of learning. We gained insight into the role of auditory information in structuring sleep activity, which in turn, we speculate interacts with daytime activity to drive vocal learning," Nature quoted Margoliash, as saying.

Since the changes occur in the region of the brain that drives singing during the day, but occur prior to the changes in singing, this discovery provides a compelling hypothesis for how this learning might happen.

Juvenile songbirds show a complex, sleep-dependent circadian patterns of singing that have been observed during developmental vocal learning.Their songs have less structure each morning and regain their complexity each afternoon. This daily pattern of variation is important for song learning-birds that have the greatest variation early in development are the ones that ultimately learn the best.

"We now have a new model for how this works. At night, the auditory information that the bird was exposed to during the day is reactivated, [carried by the spontaneous activity of neurons], changing the structure of the neural networks. These changes interact with changes during the day as birds listen to tutor songs and practice singing," said Margoliash.

According to the researchers, reactivation of sensory information at night might be a general mechanism for learning a new skill.

The study is published in this week's issue of Nature. (ANI)