Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bird brains show how trial and error may contribute to learning

10.02.2005


The adult male zebra finch knows only one scratchy tune learned in its youth, which it performs repeatedly and intensely when females are listening. But occasionally, the finch might improvise, experimenting with a slower, more sultry variation or emphasizing different notes.



Neurobiologists studying the finch now say the improvisation arises from a component of a crucial learning circuit in a section of the forebrain that seems to generate the trial and error necessary to master sophisticated motor skills, such as singing in birds or speech and sports in humans.

"It means this part of the brain is important for instructing or allowing changes in the song," said Mimi Kao, first author of a paper in the February 10, 2005, issue of the journal Nature that demonstrates how the region modulates bird song in real time. Kao, a Howard Hughes Medical Institute (HHMI) predoctoral fellow, is in the final months of her doctoral training in the laboratory of co-author Allison Doupe at the University of California, San Francisco’s Keck Center for Integrative Neuroscience.


A similar brain pathway in humans may explain how children learn to talk by listening to themselves and others, and how adults learn and hone new motor skills, such as tennis. The process relies on feedback about what works and what doesn’t, also called experience-dependent or performance-based learning.

"That all requires paying attention to how we’re doing, experimenting with different things, and gradually getting better," said senior author Michael Brainard, assistant professor of physiology at UCSF, whose lab is funded in part by a grant from HHMI. "It makes sense that one part of the brain has as part of its job introducing that kind of variability."

Kao began with an experiment to stimulate the region of the forebrain called LMAN (lateral magnocellular nucleus of the anterior nidopallium). In the avian brain, LMAN receives input about complex movements from the basal ganglia and forwards the information to motor neurons that participate in song production. Without LMAN, scientists have long known, a young bird cannot learn its song, but an adult bird can sing its song without that region of the brain. A postdoctoral fellow on another project had noticed greater and more variable brain activity when the finches were singing to themselves compared to when they were serenading females. Kao wondered whether she could cause changes in bird song by manipulating this region.

Learning takes some time, so Kao expected to wait for her results. But stimulating the LMAN had an immediate impact. The tune and rhythm of the basic song did not change, but a tiny burst of electricity would show up a few notes later as a change in volume or pitch at a particular time in the song.

The variations are usually too subtle for human ears, Kao said, but sensitive recording equipment can detect them. The systematic trials were possible with the aid of a computer program that could track the bird twitters and trigger stimulations to LMAN at precise moments to elicit measurable effects on a predetermined syllable, song after song.

The researchers found that different areas of LMAN tuned the same note in different directions, one area raising the pitch of a certain note and another area lowering its frequency. The moment-by-moment influence of this brain region on song is a new observation, Brainard said.

Next, the researchers analyzed the relationship between song and the natural neural activity of LMAN during the two types of male finch song, the performance-quality song directed at females, accompanied by some posturing and feather plumping, and the experimental solo variations, called "undirected," akin to singing in the shower. The brain region showed greater activity and more variable signaling during the undirected song, suggesting that this area is generating the variations of solo song.

Finally, they showed that birds with damage to that region of the brain lost their improvisational ability. In birds without a functioning LMAN, Kao and her colleagues still found differences between the two types of songs, but the solo song lost its subtle variations.

"In a nutshell, our paper suggests that the basal ganglia play a special role in generating motor variability," Brainard said. "It’s been known for a long time that this circuit is important in learning. Our data supports the hypothesis that one of the things it could be doing is introducing variability."

Other researchers in the Brainard and Doupe labs are following up to see if the male mating song can be permanently altered by LMAN stimulation and whether females prefer the stable or variable song version.

Jennifer Donovan | EurekAlert!
Further information:
http://www.hhmi.org

More articles from Life Sciences:

nachricht Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care

nachricht Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>