Jaideep Mavoori, a University
of Washington researcher,
spends a lot of time thinking
about communications—not
telephone or radio, but the
sophisticated network that is
the human body's nervous system. He's
most interested in helping people, afflicted by injury or disease, rebuild their ability
to control voluntary body movements.
"We want to help people get back at least
some of what they've lost," he says.
The brain acts like a central processor
for the body's nervous system. Neurons in
the brain's motor cortex send signals
through the spinal cord to control the contraction of specific muscles. When this
pathway is disrupted by something like an
accident or stroke, patients can lose the
ability to voluntarily move their arms, legs,
and other body parts.
After reading research that suggested
the brain's nerve signals can be harnessed to create changes within itself and
help it find new communications pathways, Mavoori and his University of Washington co-researchers, Andrew Jackson
and Eberhard Fetz, developed a chip that
could help people restructure their brains
to restore lost physical abilities.
The researchers used physiology, biophysics, and electrical engineering to develop a circuit that could enable the
brain to establish new motor cortex nerve
connections. The tiny self-contained
device, incorporating a processor chip,
senses neural activity in real time and
then converts the data into a stimulus
that can be sent to another area of the
brain (). The brain then
remaps its internal processes and creates
a new pathway it can use to compensate
for impaired pathways.
The researchers placed the external
prototype on top of the heads of several
monkeys. When the device continuously
connected neighboring brain sites into
the motor cortex, it produced long-lasting
positive changes. Specifically, the movements at the stimulation site changed to
resemble the signals drawn from the
recording site.
Mavoori says the best explanation for
the change is a strengthening of pathways
within the motor cortex from the recording
to the simulation site. "This strengthening
may be developed by the device's continuous synchronization of activity between
the two sites," he says.
The prototype uses a tiny lithium-ion
battery. But Mavoori believes that once
the circuitry is condensed into an
implantable chip, it may be possible for
the technology to scavenge energy from
the body itself. "It could be by using temperature differences or energy from
movement," he says.