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Topic Name: Single neuronal recordings using movable microprobes
Category: Biodesign
Research persons: Jit Muthuswamy
Location: Arizona State University,The Biodesign Institute at ASU,
1001 S. McAllister Ave.,PO Box 876001,Tempe, AZ 85287-9709,Phone (480) 727-8322Fax (480) 727-8395, United States
Details
Imagine a brain implant device smart
enough to maneuver around inside a person’s skull. On its own, the device can
locate the most functional target area to do its work. The task might involve
deep brain stimulation therapy for a patient with Parkinson’s disease. Or it
might include powering the robotic arm of a person who has lost limb
control.Such devices are known as moveable brain implants. They are realistic,
not science fiction, thanks to work by researchers in the Neural
Microsystems Laboratory at Arizona State University’s Fulton School of
Engineering.
Medical scientists use a variety of
brain implants to sense electrical and chemical activity in the brain. They can
study single neurons or ensembles of neurons. But these implanted devices often
fail over a period of time, according to Jit Muthuswamy, an ASU bioengineering
professor.
Failure is a result of natural tissue
movement or inflammation around the implant site. Drifting caused by the
devices’ positioning mechanisms also can contribute to movement and
less-than-optimal connections between the implant and targeted neurons. The very
cells that the device is seeking to connect with sometimes drift away. All of
this happens as part of the body’s natural defense mechanism to foreign bodies
and intrusive substances.
“The real challenge is learning how
to maintain a reliable interface between a single neuron and a probe,” says
Muthuswamy. “Very precise positioning is the key to success,”
He says that current implant fall short
in this respect. They require invasive brain surgery. And they cannot be
repositioned once surgically implanted into the brain.
Muthuswamy describes the devices he and
his colleagues are building. “Our probes can be moved independently, using
micromotors,” he says. “We can reposition the electrodes precisely where we
want to and have the maximum efficacy of brain stimulation.”
The motorized portion of the implant is
half the size of a human thumbnail. It resembles a wafer-thin microchip. It
would be positioned outside the brain, possibly under or outside the skull.
“Only the probes that radiate out
from the chip actually touch the brain,” Muthuswamy says. He explains that a
few small upward-downward correctional adjustments will generally reestablish a
connection with specific neurons.
At present, doctors and physiologists
would be responsible for repositioning the probes to achieve optimal outcomes.
But in the future, the ASU research team thinks that microprobes will move
within the brain in an autonomous fashion. They will have the ability to
precisely reposition themselves when necessary.
Muthuswamy and a team of ASU
researchers are also testing the devices for performance in humid environments.
Chemical, electrical, and biological testing also must be completed.
“Prostheses for the retina and the
cochlea, as well as emerging cortical prostheses can be powered by brain
implants. Such devices are already raising exciting possibilities,” says
Muthuswamy. “These technologies are critically dependent on precisely sensing
specific neurons of interest and maintaining connectivity with those neurons
during the patient’s life.”
The ASU researcher thinks that brain
implant research has other applications as well. Implants might enhance the
efficiency of deep brain stimulation therapies for individuals suffering from
Parkinson’s disease or seizures. There might also be future applications for
stroke victims or for individuals suffering from schizophrenia and other
currently incurable brain disorders.
About researchers:
Jit Muthuswamy
Arizona State University
Assistant Professor of Bioengineering
Contact Information
E-mail: jit@asu.edu
Phone: (480) 965-1599
Funded:
Brain implant research at ASU is
supported by the National
Institutes of Health, the
Whitaker Foundation, and the
Arizona Biomedical Research Commission, in collaboration with researchers
from Sandia
National Laboratories of New Mexico.
New Funded-Grant
advances neuroscience project
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