To start Year 2000 with some good news : :-)
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By Ellen Kuwana
Neuroscience for Kids Staff Writer
November 16, 1999
Progress
Research in animals such as rats, lizards, and birds has shown that new
neurons are produced in the part of their brains called the hippocampus. This
production of new neurons is called neurogenesis. It
was a logical step for scientists to suspect that neurogenesis might also
occur in adult humans. They were correct.
About a year ago, research showed that new neurons were produced in the
hippocampus of human brains. Now scientists are looking at parts of the brain to
see if new neurons are produced there, too.
To look for new neurons, researchers use a chemical called bromodeoxyuridine,
or BrdU for short. BrdU is incorporated into new cells, thus making them
distinguishable from old cells. When researchers examine brain tissue, they can
look for cells that contain BrdU.
Dr. Elizabeth Gould, a professor of Psychology at Princeton
University,
has reported recently (Science, October 15, 1999) that new
neurons are
added to other parts of the brain in adult macaque monkeys.
These areas
include those involved in "higher functions" such as
learning, problem
solving, and memory. Dr. Gould and her research group saw the
generation of neurons in the prefrontal cortex, inferior
temporal cortex,
and the posterior parietal cortex. Each of these areas has
been implicated in cognitive functions. The
prefrontal region is thought to be involved in short-term
memory and decision making; the inferior
temporal area contributes to visual recognition (e.g.,
recognition of faces); and the posterior parietal
cortex aids in interpreting the positions of objects in
space.
There is some evidence that the new cells are functional. The cells originated
in the subventricular zone,
an area around the ventricles, the fluid-filled cavities deep within the
brain. These cells then migrated
from this area to the cortex, where they developed axons. The fact that the
new cells formed axons
suggests that they are functioning.
This new study indicates that neurogenesis in the brain is more widespread
than previously thought. If
researchers can find out how new neurons appear, what conditions are necessary
for generating new
neurons, what factors need to be present or what chemicals must be absent,
perhaps this information
can be used to fight neurodegenerative diseases. Answers to these questions
may provide treatments for
disorders such as Alzheimer's disease and Parkinson's disease.
References:
1."Neurogensis in the Neocortex of Adult Primates," by E. Gould, A.J. Reeves,
M.S.A. Graziano and C.G. Gross. Science, 15
October 1999.
2."Princeton University Press Release." Scientist Discover Addition of New
Brain Cells in Highest Brain Area, October 14, 1999.
3."Science Friday Brain Update."
4."Do Brain Cells Regenerate?" Princeton Weekly Bulletin, April 5, 1999.
--
Cheers,
Joao Paulo - Salvador,Bahia,Brazil
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