UNC-Duke Scientists Develop Interactive Learning Tool Simulating Nerve Function

Stored on a CD-ROM, the new simulator opens a door into neurobiology education that allows students to duplicate experiments and extend them beyond what can be done in the laboratory. With its 17 tutorials organized into progressive levels of difficulty, it can be used selectively by undergraduate, graduate, or medical students. Unlike static images in textbooks, the simulator displays movies of changing voltage patterns at each point throughout a nerve cell.

"This offers students a natural way to envision what's happening to voltage or current patterns under an almost infinite variety of conditions," says Ann E. Stuart, Ph.D., professor of cell and molecular physiology at UNC School of Medicine in Chapel Hill. "It provides insight into nerve activity that's simply not possible with conventional text and figures or even with real experiments."

According to Stuart, the idea for "Neurons in Action: Computer Simulations with NeuroLab," came from her husband John W. Moore, Ph.D., professor emeritus in the department of neurobiology at Duke University Medical Center.

At Duke about fifteen years ago, Moore and Michael L. Hines, Ph.D. (now at Yale) began writing NEURON, a research tool used today by computational neuroscientists worldwide to model nerve function. This professional tool employs the set of Hodgkin-Huxley equations formulated in the 1950s that describe the electrical signals generated in the nerve cell. Fifty years later these equations remain the reference standard for description of electrical activity in biological systems.

"My husband decided it would be wonderful to take NEURON, which is complex and designed for professionals, and harness its power in a set of tutorials as an educational tool," Stuart said.

For the Neurons in Action tutorials, a student does not need to know programming. The tutorials offer opportunities to perform experiments on nerve cells by specifying a variety of conditions: the neuron's geometry, channel density, degree of myelination (protective sheath), environmental temperature, and ionic environment. Hyperlinks lead the student to background information, including original classic papers on the CD-ROM, to help them interpret their observations.

"The NeuroLab simulator is designed to give students the chance to explore important neurophysiological problems in far greater depth than is typically offered in conventional textbooks," Stuart said.

These problems may include issues pertaining to clinical events, such as multiple sclerosis. MS, a progressive disease of the central nervous system, involves loss of the neuronal myelin sheath and with it nerve function. For many, its symptoms worsen during very warm weather or exercise.

"We can go into the 'change temperature' section of a tutorial and cool the nerve cell by the tiniest bit, one-tenth of a degree. The student sees that function is now restored to the demyelinated portion of the nerve. Links explain why," Stuart explained.

"Each of the tutorials has its own set of parameters you can fuss with and each of them leads you through a series of problems and ultimately to the answers. In the lab you can take the whole afternoon to do one of these experiments. But with the NeuroLab simulator you can sit at your computer and do experiment after experiment.

"For scientific subjects that can be described quantitatively, I think this represents the wave of the future."

Neurons in Action is published by Sinauer Associates, Sunderland, Massachusetts.