COLLOQUIUM Department of Computer Science and Engineering University of South Carolina Information Coding in Nervous Systems: Responses to Regular and Irregular Discharges Michael Stiber Computing and Software Systems Program University of Washington, Bothell Date: June 24, 2003 (Tuesday) Time: 2:00-3:00PM Place: Swearingen 1A03 (Faculty Lounge) Abstract The nervous systems of animals are the most sophisticated computational devices known, exquisitely suited to processing information and controlling behavior to aid in the survival of organisms. Despite decades of work and enormous advances in neuroscience, we are still largely in the dark regarding some of the most basic principles of neural information coding. In this talk, I present the results of an ongoing investigation into information coding in biological nervous systems. Using the recognized embodiment of a prototypical inhibitory synapse---the crayfish slowly adapting stretch receptor organ (SAO)---and nonlinear dynamical models, my collaborators and I have previously examined coding of periodic and smoothly varying inputs. Here, I discuss my most recent work, which seeks to extend these results to arbitrary neural inputs. More specifically, I examine the implications of input timing precision for information coding. The apparent lack of precision, or noisiness, of neurons is a common observation in the neuroscience literature, based on their discharges looking "messy" and the fact that multiple experiments with identical stimuli produce different responses. However, these observations are based on weak definitions of neuronal noise. Using a well-validated physiological model of the SAO, I demonstrate how highly precise input timing can be used to support error correction coding and discuss the utility of different dynamical behaviors in neurons for error correction. Michael Stiber received a BS in Computer Science and a BS in Electrical Engineering from Washington University, Saint Louis, in 1983, and his MS and PhD in Computer Science from the University of California, Los Angeles. He held positions with Texas Instruments (Dallas, Texas), Philips (Eindhoven, Netherlands), and the IBM Los Angeles Scientific Center. He was an Assistant Professor in the Department of Computer Science at the Hong Kong University of Science and Technology during 1992-96 and a Research Assistant Professor in the Department of Molecular and Cell Biology at the University of California, Berkeley in 1996-97. Dr. Stiber is a frequent visitor to the Department of Biophysical Engineering at Osaka University (Japan). He is on the executive committee of the Seattle section of the IEEE Computer Society, has served on organizing committees, chaired sessions, and reviewed papers for neural network and computational neuroscience conferences, and is a reviewer for Biological Cybernetics, Physica D, The Journal of Computational Neuroscience, and the Bulletin of Mathematical Biology. He is an avid gardener who enjoys mixing the ordinary and unusual in his home landscape.