Hello Tweeties,

I just want to share this article (long) about how
birds are helping scientists to understand how the
brain works.

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http://www.wired.com/news/medtech/0,1286,65507,00.html

Don't Knock the Birdbrains
By Randy Dotinga

Oct. 29, 2004 PT

SAN DIEGO -- Three decades after researchers first
fathomed the unusual brain power of songbirds,
scientists are devoting big chunks of their careers to
finches and canaries, hoping to understand how they
manage to be among the only species that learn how to
make new sounds.

Even though their brains range from just the size of a
grain of rice to peanut-size, some types of songbirds
can still pick up hundreds of songs during their
lives. They improvise the songs like miniature jazz
singers and even develop regional accents depending on
where they live.

Scientists at this week's annual Society for
Neuroscience convention in San Diego said research
into bird songs can lead to greater understanding of
human speech and the mysteries of how animals develop
new neurons and memorize things. It helps that bird
brains are small, leaving few places for singing
abilities to hide.

"We know the human brain is capable of this, but we
don't know where to look for it," said Peter Marler,
professor emeritus of neurobiology at the University
of California at Davis, who helped pioneer the study
of songbirds in the early 1970s. "We know virtually
nothing about the detailed circuitry,"

Countless animals make sounds, but the noises are
almost all preprogrammed in the brain, not learned. A
cat, for example, will meow and purr from birth. But
it won't imitate anyone or pick up new sounds. "The
cat will create these vocalizations even in the
absence of any other cat in its life," said Robin
Ashmore, a neuroscience graduate student at the
University of Pennsylvania.

Humans and a few other kinds of animals -- including
songbirds, bats, dolphins and whales -- are more
complicated. They make some sounds automatically --
think of a human baby crying. But they pick up other
sounds through "vocal learning," a kind of imitation
that draws on their own internal databases of sounds.
"The amazing thing is that this ability is so rare,"
Marler said.

Songbirds learn sounds through a process akin to the
error-checking routine that goes into burning a CD.
Songbirds, which are typically male, listen to a song
from another bird, such as their father. Pulling
sounds from the "toolbox" in their brain, they try to
imitate the song, Ashmore said. "They listen to
themselves sing, and make some sort of comparison with
the song they have in their brain," he said. Then they
adjust the song.

"It's a really good, concise example of how brains can
acquire, store and use information," Ashmore said.

In neuroscience laboratories at several universities
across the United States, researchers are studying two
types of songbirds -- canaries and zebra finches.
Other
kinds of songbirds, such as mockingbirds, are also
getting attention, along with the hummingbird and the
eternally imitative parrot.

At Wesleyan University in Connecticut, researchers are
using Botox, the same neurotoxin that zaps facial
wrinkles and expressions, to paralyze the vocal cords
of zebra finches so they can't sing well. Apparently,
the birds realize something is wrong by listening to
themselves -- think of the audio feedback a musician
gets from speakers on stage -- and essentially have to
start from scratch. As they relearn their songs, they
create new neurons in the process.

Neurons are a huge topic in neuroscience because
researchers have only recently discovered that they
routinely regenerate. For decades, scientists thought
animals didn't grow new neurons after the first few
years of life. The idea that they can actually
regenerate has spurred hopes for potential treatments
for diseases like Alzheimer's that kill off brain
cells.

Songbirds also attract interest because their songs
appear to be closely related to human speech. "The
parallels ... are very strong," said David Vicario,
associate professor of psychology at Rutgers
University.

Just like people, songbirds have regional accents. And
-- just as people do -- it's possible songbirds may
"lose" preprogrammed sounds if they don't use them
early in life; if they don't sing a certain sound,
their brains may discard it from their repertoire.

Humans definitely have that problem. Linguists think
if we don't use a sound early in life, we lose the
ability to make it because of some sort of routine
cleanup of extraneous brain space. This explains why
young children can learn second languages with an
accurate accent; if they learn another language later,
their brains may have already trashed some of the
sounds they'll need to speak it perfectly.

Songbirds know how to improvise -- a trait that's also
shared with humans. For reasons that aren't clear,
they'll copy 90 percent of another bird's song but add
variations of their own to the other 10 percent,
Vicario said. According to him, this improvisation may
help prevent incest by differentiating between the
songbirds in a family so a female won't mate with the
wrong male.

ndeed, mating is the main motivation behind birdcalls,
although they can also help birds declare their
territory. Typically, only male songbirds sing --
although in some species females and males sing duets
-- and they often develop repertoires of hundreds of
songs. Why? "The more you sing, the more the female is
stimulated. But females get bored," said Marler, the
UC Davis songbird pioneer. "If you can switch from
song to song, that's much more interesting."

Like humans, single songbirds can have play lists of
hundreds of songs. But unlike people, sparrows and
parrots -- which are not "fantastic thinkers," as
Marler puts it -- can't follow up with conversation
and sweet nothings.

"We learn these new sounds, then we attach new
meanings to the sounds we've learned and combine them
in different ways to create sentences," he said.
"We've crossed the Rubicon."


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Devorah A. N. Bennu, PhD
Independent Scholar and
Research Associate,
American Museum of Natural History
birdologist [at] yahoo [dot] com
public blog: http://girlscientist.blogspot.com



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