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Location: UFOUpDatesList.Com > 2007 > Apr > Apr 5

Key To Grey Manipulation Or Too Much X Files?

From: Rick Nielsen <nilthchi.nul>
Date: Thu, 5 Apr 2007 05:31:03 -0700 (PDT)
Fwd Date: Thu, 05 Apr 2007 09:04:08 -0400
Subject: Key To Grey Manipulation Or Too Much X Files?

Key To Grey Manipulation Or Too Much X Files?


Source: Science Daily - Herndon, Virginia, USA


April 5, 2007

Stanford University

Scientists Directly Control Brain Cell Activity With Light

Science Daily =97 Every thought, feeling and action originates from
the electrical signals emitted by diverse brain cells enmeshed in
a tangle of circuits. At this fundamental level, scientists
struggle to explain the mind. Worse yet, they have lacked tools
to understand what's going wrong in patients with ailments such
as depression or Parkinson's disease. New Stanford-led research
published in the April 5 issue of Nature describes a technique to
directly control brain cell activity with light. It is a novel
means for experimenting with neural circuits and could eventually
lead to therapies for some disorders.

"This accomplishment is a key step toward the important goal of
mapping neural circuit dynamics on a millisecond timescale to see
if impairments in these dynamics underlie severe psychiatric
symptoms," said National Institutes of Health (NIH) Director
Elias A. Zerhouni. "The work is also a prime example of the
highly innovative approaches to major challenges in biomedical
research that we support through the NIH Director's Pioneer Award

Karl Deisseroth, an assistant professor of bioengineering and of
psychiatry who led the research group that authored the paper,
received the NIH award in 2005.

"This research provides a tool that we didn't have before, which
is precise on-or-off control over specific neural cells in living
creatures and intact circuits," says Deisseroth, whose Stanford
research group collaborated with researchers at the Max Planck
Institute of Biophysics, the Johann Wolfgang Goethe University in
Frankfurt and the University of W=FCrzburg in Germany. "This gives
us the power to ask what the causal role of specific cell types
is in neural circuit function."

Knowing the effects that different neurons have could ultimately
help researchers figure out the workings of healthy and unhealthy
brain circuits, explains graduate student Feng Zhang, a lead
author of the paper along with Stanford postdoctoral scholar
Li-Ping Wang. If use of the technique can show that altered
activity in a particular kind of neuron underlies symptoms, for
example, this insight will allow development of targeted genetic
or pharmaceutical treatments to fix those neurons. Conceivably,
direct control of neuronal activity with light could someday
become a therapy in itself.

A neural traffic light
To selectively take control of neurons, the researchers used a
virus to insert genes for producing light-sensitive proteins into
cells of interest. The gene ChR2 is derived from an algae that
makes affected neurons more active when exposed to blue light.
Deisseroth and collaborators first showed this in a paper in
Nature Neuroscience in 2005. In this week's paper, they
demonstrate that another gene, NpHR, which is borrowed from a
microbe called an archaebacterium, can make neurons less active
in the presence of yellow light. Combined, the two genes can now
make neurons obey pulses of light like drivers obey a traffic
signal: Blue means "go" (emit a signal), and yellow means "stop"
(don't emit).

In the new paper, the group shows this technique can have
immediately observable effects in living creatures. The Stanford
team's collaborators in Germany were able to cause tiny worms
called C. elegans to stop swimming while their genetically
altered motor neurons were exposed to pulses of yellow light
focused through a microscope. In some experiments, exposure to
blue light caused the worms to wiggle in ways they weren't
moving while unperturbed. When the lights were turned off, the
worms resumed their normal behavior.

Meanwhile, in experiments in living brain tissues extracted from
mice at Stanford, the researchers were able to use the technique
to cause neurons to signal or stop on the millisecond timescale,
just as they do naturally. Other experiments showed that cells
appear to suffer no ill effects from exposure to the light. They
resume their normal function once the exposure ends.

Potential applications
The most direct application of optical neuron control is to
begin experimenting with neural circuits to determine why
unhealthy ones fail and how healthy ones work.

In patients with Parkinson's disease, for example, researchers
have shown that electrical "deep brain stimulation" of cells can
help patients, but they don't know precisely why. By allowing
researchers to selectively stimulate or dampen different neurons
in the brain, the new Stanford technique could help in
determining which particular neurons are benefiting from deep
brain stimulation, Deisseroth says. That could lead to making
the electrical treatment, which has some unwanted side effects,
more targeted.

Another potential application is experimenting with simulating
neural communications. Because neurons communicate by generating
patterns of signals-sometimes on and sometimes off like the 0s
and 1s of binary computer code-flashing blue and yellow lights in
these patterns could compel neurons to emit messages that
correspond to real neural instructions. In the future, this could
allow researchers to test and tune sophisticated neuron
behaviors. Much farther down the road, Deisseroth speculates, the
ability to artificially stimulate neural signals, such as
movement instructions, could allow doctors to bridge blockages in
damaged spinal columns, perhaps restoring some function to the
limbs of paralyzed patients.

Finally, the technique could be useful in teasing out the largely
unknown functioning of healthy brains.

"One day we'd like to be able to understand the organization of
the brain," Zhang says. "How do different types of cells
communicate with each other to carry out very complex things like
emotion or how people make decisions?"

Funding for the paper's authors comes from NIH, the California
Institute of Regenerative Medicine, the Max Planck Society, the
Deutsche Forschungsgemeinschaft (German Research Foundation), the
German government, the National Alliance for Research on
Schizophrenia and Depression, the American Psychiatric Institute
for Research and Education, and the following foundations:
Snyder, Culpepper, Coulter, Klingenstein, Whitehall, McKnight,
and Albert Yu and Mary Bechmann.

Note: This story has been adapted by Science Daily from a news
release issued by Stanford University.


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