BIOMEDICAL ENGINEERING

Unlocking the brain

Assistant Professors Justin Williams (above right) and P. Charles Garell (above left).

Assistant Professors Justin Williams (above right) and P. Charles Garell (above left, also director of functional neurosurgery at UW Hospital). (28K JPG)

IF YOU THINK about moving your arm, the neurons in your brain send electrical information, like electricity flowing through computer wires, to make it happen. But for people with ALS, high spinal-cord injuries or brainstem strokes, the neurons that transmit information from the brain to the body are damaged, “locking” the electrical signals that control motion inside the brain.

Collaborating with researchers at Washington University, the University of Washington and the Wadsworth Center at the New York State Department of Health, Assistant Professors Justin Williams and P. Charles Garell (also director of functional neurosurgery at UW Hospital) and graduate students Elizabeth Felton and Adam Wilson are studying a unique combination of mind and machine that may help people with those diseases regain their ability to communicate — and ultimately, to move.

Neurosensors

Neurosensors (25K JPG)

The key is placing tiny neurosensors, which detect neurons’ electrical signals, directly on certain parts of the brain. If a patient thought about moving her left arm, a sensor could read the signal, then send the information via wires to a processor to translate it into an action — in this case, moving a cursor on a computer screen.

The group is working with Garell’s severe epilepsy patients, who already have temporarily implanted sensors that identify the origin of their seizures. Within minutes, the patients learn to move a cursor by thinking about a certain motion or sound, which corresponds to a single sensor’s location on the brain.

The researchers are among the first to place the devices on the brain, rather than on the scalp (the skull “muddies” the brain’s information). From the epilepsy patients, they hope to learn what parts of the brain are best-suited for permanent sensors and whether patients’ control of the cursor could become effortless over time.

It's no shock: Tasers may be much safer than bullets

IN JUST A FEW SECONDS, a Taser delivers rapidly pulsed current that contracts recipients’ muscles and temporarily “paralyzes” them. Law enforcement officers often use the dartfiring device to subdue potentially dangerous or fleeing suspects, rather than injuring them with bullets. Its use, however, is under fire: Some groups state that within the past few years, more than 100 people have died after receiving Taser shocks.

An expert in electrical conduction through the body, Professor Emeritus John Webster is conducting the first independent investigation into whether Tasers are, in fact, a safer alternative to bullets. His study, funded with $500,000 from the U.S. Department of Justice, aims, initially, to determine if the devices directly electrocute the heart.

Webster and his students developed computer models that show the most dangerous locations for Taser darts are those closest to the heart. They are determining the distance from the skin to the heart, which varies based on a person’s size and weight. Conducting controlled tests on anesthetized pigs (which feel no pain), they are verifying their models and determining how much electricity is required to electrocute the heart.

Webster’ hypothesis is that Tasers do not directly electrocute the heart; thus, to learn more about why Taser-related deaths occur, he is considering cocaine use as a contributing factor. During their tests, he and his team also plan to take regular blood samples to determine if blood-chemistry changes (most notably, a surge in potassium due to muscular contraction) could play a role in the deaths.

Clinical trials:
Teaching patient-centered neuroengineering

The product of collaborations among more than 15 UW-Madison medical, science and engineering departments and units, the new National Institutes of Health-sponsored Clinical Neuroengineering Training Program (CNTP), administered through the department, enables students pursuing doctoral degrees to get out of the classroom and into the clinic.

Coupled with neuroscience and engineering knowledge, experience working with a clinician to solve a real-world problem in neuroscience will give students a unique trio of tools, says Associate Professor Beth Meyerand (also of medical physics and radiology), who co-directs the program with Professor Tom Yin (also of physiology). For biomedical engineers, the program might mean developing new skills in neuroscience, then working with clinicians to apply their knowledge to actual problems. CNTP students also have the unique opportunity to undertake clinical rotations, similar to those of advanced medical students.

The program’s 45-plus faculty members have expertise in areas ranging from MRI imaging, studies on the stem cell level, and sensory and learning processes of speech perception to mathematical modeling, neuromuscular diseases and optic neuropathy. Although students earn PhD degrees from traditional departments — everything from biomedical engineering, nutritional sciences and mathematics to neuroscience, ophthalmology and psychology — they have representatives from the engineering, neuroscience and clinical areas of the CNTP program on their thesis committees.

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