John Wikswo
| John Wikswo | |
|---|---|
| Born |
October 6, 1949 Lynchburg, Virginia, United States |
| Nationality | American |
| Scientific career | |
| Fields | Biological Physics |
| Institutions | Vanderbilt University |
John Peter Wikswo, Jr. (born October 6, 1949) is a biological physicist at Vanderbilt University. He was born in Lynchburg, Virginia, United States.
Wikswo is noted for his work on biomagnetism and cardiac electrophysiology.
In the 1970s, Wikswo was a graduate student at Stanford University, where he worked under physicist William M. Fairbank, studying .
In 1977 he became an Assistant Professor in the Department of Physics and Astronomy at Vanderbilt University, where he set up a laboratory to study Living State Physics. In 1980, he made the first measurement of the magnetic field of an isolated nerve, by threading the a frog sciatic nerve through a wire-wound, ferrite-core toroid and detecting the induced current using a SQUID magnetometer. At the same time, Wikswo and Ken Swinney calculated the magnetic field of a nerve axon. This work was followed a few years later by the first detailed comparison of the measured and calculated magnetic field produced by a single nerve axon.
In a related line of study, Wikswo collaborated with Vanderbilt Professor John Barach to analyze the information content of biomagnetic versus bioelectric signals.
One of Wikswo's most important contributions to science is his work in cardiac electrophysiology. In 1987 he began collaborating with doctors at the Vanderbilt Medical School, including Dan Roden, to study electrical propagation in the dog heart. These studies led to the discovery of the virtual cathode effect in cardiac tissue: during electrical stimulation, the action potential wave front originated farther from the electrode in the direction perpendicular to the myocardial fibers than in the direction parallel to them.
In parallel with these experimental studies, Wikswo analyzed the virtual cathode effect theoretically using the bidomain model, a mathematical model of the electrical properties of cardiac tissue that takes into account the anisotropic properties of both the intracellular and extracellular spaces. He first used the bidomain model to interpret biomagnetic measurements from strands of cardiac tissue. Wikswo realized that the property of unequal anisotropy ratios in cardiac tissue (the ratio of electrical conductivity in the directions parallel and perpendicular to the myocardial fibers is different in the intracellular and extracellular spaces) has important implications for the magnetic field associated with a propagating action potential wave front in the heart. With Nestor Sepulveda, Wikswo use the finite element method to calculate the distinctive fourfold symmetric magnetic field pattern produced by an outwardly propagating wave front.
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