Zebra finches are very efficient at learning their courtship songs, as researchers from ETH Zurich and the University of Zurich have shown. In the morning, the birds remember the positive learning progress of the previous day, but forget the failures overnight.
Some principles and mechanisms of learning are identical, for example, in both language acquisition and in learning different motor skills. Neuroinformaticians at ETH Zurich and the University of Zurich are looking for these basics of learning processes. For this purpose, they introduced a general framework to distil the myriad of changes occurring during a learning process into a simple "trajectory", which allows them to tell how and when a skill is changing without having to consider all the details of the involved movements. They used this novel framework to study how juvenile male zebra finches gradually learn to sing.
The learning trajectories revealed a few surprises: For one, they showed that the learning process is multi-layered, in the sense that good songs and bad songs change in different ways. For another, of the many changes in singing occurring during a day, most are reset overnight, presumably because they are unrelated to what the bird is trying to sing. "One interpretation of this is that the birds are incredibly efficient. Sleep allows them to perfectly remember all the good things they learned during the day, and to forget all the things that are not important," explains Valerio Mante, professor at the University of Zurich.
"We think that the brain processes involved in this learning might be analogous to the ones at work in humans when they learn a motor skill," says Richard Hahnloser, professor of neuroinformatics at ETH Zurich. One great advantage of studying this process in birds is that the researchers have much more precise tools to observe what is happening in the brain during the learning process.
The observed processes are the basis for a better understanding what happens in the brain during learning. According to the scientists, this knowledge has great therapeutic potential. If we could understand why it is so hard to remember improvements in bad parts of a behaviour, more efficient training schedules could be developed in rehabilitation for adults recovering from a stroke or accident. Ultimately, it might even be possible to improve and stimulate learning and consolidation by intervening directly in specific brain areas.
Kollmorgen S, Hahnloser R, Mante V: Nearest neighbors reveal fast and slow components of motor learning. 8 January 2020. doi: 10.1038/s41586-019-1892-x