Computer Chips Help Rewire Muscle Controls

Scientists are now using computer chips to help repair the human nervous system. A stroke or a spinal-cord injury can cause nerve damage that results in the loss of muscle control. Computer chips can help create new connections in the brain, effectively rewiring the connection between the brain and muscles.

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A stroke or a spinal cord injury can damage the nerve networks that control our muscles. Repairing the damage isn't easy. The body can help by naturally rewiring the network so nerve signals can get through. Scientists are now using things like computer chips in hopes of greatly improving the repairs.

NPR's Jon Hamilton reports.

JON HAMILTON: Back in the 1980s, scientists argued about whether it was even possible to repair circuits in the brain and the nervous system. These days, the debate is about which technology to use. Here is Dr. Robert Levy of Northwestern University.

Dr. ROBERT LEVY (Northwestern University): This technology will be applied in a routine clinical setting to help relieve the suffering of our patients. And 10 years ago, I would have said that it will be lifetimes before we see that. I'm expecting to see these things in general clinical use before I retire.

HAMILTON: Levy says his optimism is based on a series of remarkable experiments in animals and people. The most recent comes from the University of Washington. Researchers there used a tiny computer chip to create a new connection in the brain of a monkey.

Eberhard Fetz was part of the team. He says the experiment involved two areas in the monkey's brain that control two different muscles in the monkey's wrist. Ordinarily, these brain areas don't talk to each other. But Fetz says his team used a computer chip to create an artificial connection. When the chip detected signals coming from the first area, it immediately sent an electrical pulse to the second.

Dr. EBERHARD E. FETZ (Researcher, University of Washington): So we have two different areas controlling different muscles that are connected by this artificial feedback loop.

HAMILTON: But the big question was whether the two brain areas would keep communicating without the computer chip. Fetz says they did.

Dr. FETZ: Even after the circuit was turned off, this change remained for five days or more.

HAMILTON: The researchers had succeeded in rewiring a tiny portion of the monkey's brain. Fetz says that's only a small step toward repairing major damage. But he says the experiment suggests a number of approaches that might help human patients recover.

Dr. FETZ: For example, in spinal cord injury or peripheral nerve damage, the brain is fine, the muscles are fine, but the connection is lost, and this computer interface could create an artificial bridge from the cortical cells to the muscles.

HAMILTON: Randolph Nudo of the University of Kansas Medical Center says electrical stimulation also might help people paralyzed by a stroke.

Dr. RANDOLPH NUDO (Professor, Department of Molecular and Integrative Physiology, University of Kansas Medical Center): We don't just have one motor area in our brains; we have multiple motor areas. And if one of them is injured, it becomes disconnected from other parts of the brain.

HAMILTON: Nudo says a computer chip might be able to help reestablish those connections.

Robert Levy is part of a team at Northwestern that's already using electrical stimulation to help stroke patients who've lost some use of an arm or hand.

Dr. ROBERT LEVY (Professor of Neurological Surgery, Northwestern University): The point of our work is to move the function away from an area of damaged brain to an adjacent area of brain that is not damaged to assume some of that function.

HAMILTON: In other words, to create an entirely new connection between the brain and a specific set of muscles. Levy says they do this by electrically stimulating a selected site in the brain while a patient is undergoing physical therapy. And Levy says early results suggest the approach is working.

Dr. LEVY: There are significant and lasting improvements in the ability of patients to move their arm and their hand and to perform critical activities of daily living.

HAMILTON: Like holding a fork. Levy says he's conducting a clinical trial of electrical stimulation in about 150 patients. The study should be finished sometime next year.

Jon Hamilton, NPR News.

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