Professor of Biophysics
Director, Center for Neurodynamics
Department of Physics and Astronomy
University of Missouri at St Louis
One University Boulevard
St. Louis MO 63121
Editor of The Journal of Biological Physics, published by Springer.
THE ESSENTIAL TENSION: Competition, Cooperation and Multilevel Selection in Evolution
Phase transitions in yeast and bacterial populations under stress
Computational models of phase transitions in evolutionary dynamics
We are investigating the role of mutation parameters in driving speciation in evolutionary models. We have observed phase-transition-like behavior as the maximum mutation size is varied, on various types of fitness landscapes. Optimal clustering, which can be considered as an analog of speciation, occurs for an intermediate mutation parameter. Our first work on this model appeared in PLoS ONE. More recently, we have found similar behavior even on a NEUTRAL landscape, in which all simulated organisms have identical fitness.
NEURAL SYNCHRONIZATION
Recent doctoral student Daisuke Takeshita (Ph.D. 2010, now Associate Professor at the University of Tokyo) studied the synchronization of neural activity in the rat neocortex during focal seizures. Using voltage-sensitive-dye imaging, Daisuke demonstrated a sharp rise in synchronization during seizures. This study appeared in the journal Chaos, in a focus issue honoring Frank Moss.
Recent doctoral student Roxana Contreras (Ph.D. 2009), studied eye-target synchronization in normal subjects and mild traumatic-brain-injured (mTBI) patients. Her most recent work in this area appeared in Brain Research in 2011.
EVOLUTION OF FORAGING STRATEGIES
Recent doctoral student Nathan Dees (Ph.D. 2009), who now works at the Genome Center at Washington University in St. Louis, studied the evolution of optimal foraging behavior in various species, ranging from Daphnia to paddlefish. He also investigated how nonlinear dynamical techniques can reveal the relationship between the fMRI-BOLD signal and EEG recordings in human subjects.
In vivo imaging of seizure activity in the rat neocortex...
....and human intraoperative brain imaging (postdoctoral work with Ted Schwartz)
Neural synchronization in the crayfish caudal photoreceptor (postdoctoral work with Frank Moss)
Imaging hypoxic spreading depression in rat hippocampal slices.
Bistability and hysteresis in the response of periodically paced small pieces of bullfrog cardiac tissue. Phys. Rev. Lett. 82:2995-2998, 1999.
Spatiotemporal effects of bistability in coupled map models of cardiac dynamics(published in the Proceedings of the 5th Experimental Chaos Conference, Boca Raton, Florida, July 1999).
Control of fibrillation using nonlinear dynamics based methods in the in vivo sheep heart.
Bistability and Hysteresis in the Periodically Paced Sheep Heart
Monovalent and divalent anion transport in the band 3 and AE2 proteins with Phil Knauf
Time Delay Embeddings of IFS Attractors
Symbolic Dynamics for IFS Attractors
Apparently Chaotic Orbits Embedded in Closed Curves, written with Irene Hueter
