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 New photocatalyst speeds up the conversion of carbon dioxide into chemical resources
29.05.2017 | DGIST (Daegu Gyeongbuk Institute of Science and Technology)

nachricht Copper hydroxide nanoparticles provide protection against toxic oxygen radicals in cigarette smoke
29.05.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

New insights into the ancestors of all complex life

29.05.2017 | Earth Sciences

New photocatalyst speeds up the conversion of carbon dioxide into chemical resources

29.05.2017 | Life Sciences

NASA's SDO sees partial eclipse in space

29.05.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>