More than 10,000 people suffer a spinal cord injury in the U.S. each year, many of whom never recover the ability to walk. With new funding to study the neural networks for locomotion in rodents, Ronald Harris-Warrick, Cornell professor of neurobiology and behavior, hopes to find ways for spinal cord injury victims to get back on their feet.
With a grant of almost $700,000 from the National Institute for Neurological Disorders and Stroke funded by the American Reinvestment and Recovery Act (ARRA), Harris-Warrick will continue research that had previously been funded by New York state and the Christopher and Dana Reeve Foundation.
Although the brain decides when and where to walk, neural networks in the spinal cord, not the brain, give the detailed instructions for locomotion. That’s why a chicken can run around with its head cut off, Harris-Warrick says. Why, then, are humans paralyzed by spinal cord injuries?
When our spinal cords are extensively damaged, two critical systems are cut off, Harris-Warrick explains. “There’s the one that says ‘go,’ ‘stop,’ ‘turn right’ — the instructive one. The other one involves neural modulators, such as serotonin, which play an important part in enabling the network to work at all,” he said.
Harris-Warrick compares serotonin’s function in the body to the key that turns on a car’s engine. The key is essential for the car to move, though by itself it does not start the movement; the gas pedal does that. Similarly, serotonin is what keeps the body’s networks for locomotion “idling,” and we cannot walk without it. Then rapid descending inputs trigger the locomotion, like gas to a car engine.
Figuring out ways to apply an agonist to mimic serotonin in the body is a focus of Harris-Warrick’s research. His group has evidence that the agonist quipazine will help to preserve the network for locomotion in mice after spinal cord injury.
“We’re hoping to provide solid justification for how quipazine might be helpful,” he said. His group will not administer clinical trials in humans, however.
“This is the first time I’ve done research with direct clinical relevance, and I find it very interesting,” he said.
Harris-Warrick has used the grant to pay the full-time salaries of two postdoctoral researchers, provide half the salary of a third postdoc and hire a graduate student.
To date, Cornell has received 124 grants on the Ithaca campus, totaling more than $99.9 million.
Graduate student Melissa Rice is a writer intern at the Cornell Chronicle.
By Melissa Rice