From: Gina Miller (echoz@hotmail.com)
Date: Wed Apr 28 1999 - 23:32:39 MDT
Yahoo! News Science Headlines
Wednesday April 28 7:45 PM ET
Unique Neurons Make People, Apes Smart - Report
WASHINGTON (Reuters) - A unique type of brain cell seems to separate
humans and apes from lower animals, and may make them smarter,
scientists say.
But the neuron clusters come at a price -- they may make us
susceptible to diseases such as Alzheimer's, the researchers at the
California Institute of Technology and Mount Sinai School of Medicine
in New York said.
The large, spindle-shaped cells are found in humans, bonobos,
chimpanzees, gorillas and orangutans, but not any other type of
animal, Patrick Hof of Mount Sinai and his colleagues report in this
week's issue of the Proceedings of the National Academy of Sciences.
Bonobos are a type of chimpanzee recently found to be a distinct
species and more closely related to humans than other chimpanzees.
And Hof's team also found that bonobos have more of these cells than
the other apes.
``This declining concentration matches the degree of relatedness of
these apes to humans,'' John Allman of Caltech said in a statement.
The brain cells could finally offer what many people have searched
for -- a defining element that separates humans from the animal world.
Criteria have fallen by the wayside one by one with discoveries that
gerbils have a fairly sophisticated language to warn of predators,
that birds use tools and that dolphins can respond to the grammatical
structure in hand signals.
Several chimpanzees have been taught to use either sign language or
computers to communicate and have been shown to use original thought
in structuring sentences.
Hof and Allman's team looked at 28 different species of primate, and
at humans who died and had autopsies.
They found their spindle cells in the anterior cingulate cortex of
the brain, which controls automatic functions such as heart rate but
which also has been linked to emotions -- including the emotional
response to pain -- and facial expressions.
``Spindle cells were notably absent in the gibbon as well as in New
World monkeys, Old World monkeys and all of the prosimians (such as
lemurs),'' they added.
The findings show that, as biologists have long said, chimpanzees and
bonobos are the closest relatives of humans.
``The observation that among humans and great apes, chimpanzees have
spindle cell densities comparable to humans -- and it is the bonobo
whose spindle cell distribution most closely matches that of the
human -- underscores the relatedness of Homo (the human species) and
Pan (the chimpanzee species),'' they wrote.
Spindle cells in this area have also been shown to be affected in
Alzheimer's disease, the most common cause of dementia, the
researchers pointed out. This suggests that the susceptibility to
such diseases may have evolved only recently.
Copyright © 1999 Reuters Limited. All rights reserved.
Republication or redistribution of Reuters content is expressly
prohibited without the prior written consent of Reuters.
Reuters shall not be liable for any errors or delays in the content,
or for any actions taken in reliance thereon.
Gina "Nanogirl" Miller
Nanotechnology Industries
Web Page
http://www.nanoindustries.com
E-mail
echoz@hotmail.com
Alternate E-mail
nanogirl@halcyon.com
"The science of nanotechnology, solutions for the future."
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