I started out in physics and math, and my research and teaching has always reflected my interest in using physical science to understand life processes, in particular how nervous systems work. In my laboratory we are studying how nerve cells generate and propagate electrical signals, and also how nervous systems process information about the visual world. Electrical signaling in nervous systems depends on the opening and closing of voltage-sensitive ion channels in the membrane of nerve cells. The composition and basic structure of these ion channels is known, but the changes in channel structure that underlie opening and closing are not well understood. A small change in the electrical potential across a nerve cell's membrane is what causes a channel to open, so electric forces on charged atoms in the channel must be involved. Dr. Cliff Chancey and I developed a physical model of one type of channel that describes the interactions among charged atoms and predicts how parts of the channel should move under changes in the electrical state of the membrane. An intriguing possibility emerging from the model is that some channel openings may happen by a process called quantum tunneling, rather than by standard “classical” processes. We are now working to understand better both classical and quantum routes to channel opening, and to incorporate new knowledge about channel structure into the model.
My other research area of interest is the visual system, in particular how visual experience changes connections between nerve cells in that part of the brain. We use frogs for this research in my lab at Amherst, and other amphibians in a collaboration with Dr. Wang Shu-Rong and colleagues at the Chinese Academy of Sciences Institute of Biophysics in Beijing. Even in an animal with as stereotyped behavior as a frog, changes in visual experience cause changes in behavior. We study how the behavior called optokinetic nystagmus, which refers to reflex movements of an animal's head and eyes to follow moving visual fields, is affected by visual deprivation. This simple behavior is easily quantifiable in the lab, and the basic brain circuitry responsible for it is known. We are looking for alterations in connections at the level of receptor molecules at the site of connections between nerve cells to explain the effects of visual deprivation on nystagmus. Understanding this relatively simple system provides an example of the kinds of changes that may underlie brain plasticity and learning in other animals, including humans.