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Mathematicians
at Ohio State University may have found the origin of Parkinson's
disease tremors.
Researchers
constructed a computer model of electrochemical activity in
a brain affected by Parkinson's disease and found unusual
patterns in the way brain cells fired signals back and forth.
"In
a normal brain, every cell is doing its own thing, and the
signals create a random pattern," said David Terman,
professor of mathematics. "But in our model, we saw cells
firing together in lockstep, creating a synchronized pattern
that matched the timing of Parkinson's tremors."
Researchers
had previously thought that a dramatic increase in the frequency
of neural signals was the cause of tremors because during
Parkinson's episodes the neurons in a key part of the brain
fire almost twice as fast as normal. This increase in frequency
can explain symptoms such as stiffness or slowness of movement
but cannot easily explain tremor, said Terman.
"Our
computer model shows that the pattern of the signals is important,
too -- not just the frequency," said Terman.
The computer
model is a software simulation of brain cells and the electrical
signals that travel between them. Researchers were able to
reproduce the normal, random firing of brain cells. When they
simulated the loss of dopamine, like what occurs in the brains
of Parkinson's disease patients, a different pattern of firing
occurred.
Researchers
are hopeful that their findings will give them new directions
for the development of Parkinson's therapies.
Source:
Medical Week staff,
week of May 26, 2002
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