Ermentrout "Lab"

People

Postdoc

• Andrea Welsh

Graduate students

• Ka Nao Tse
• Bowei Ouyang

Recent Alumni

• Jay Pina (York, Postdoc)
• Derek Orr (PNC Bank)
• Yujie Ding (some tech place in California)
• Ericka Mochan (Chadham)
• Stewart Heitmann (U Sydney)
• Yury Sokolov (UCSD, postdoc)
• Dan Wilson (U. Tennesee, faculty)
• Jeremy Harris (Emery, postdoc)
• Glenn Young (James Madison, faculty)
• Youngmin Park (U Florida,faculty)
• Jeff Dunworth (Michigan, postdoc)
• Stefanos Folias> http://www.math.uaa.alaska.edu/~sfolias/ (Asst Prof, U. Alaska)
• Zack Kilpatrick (Prof, U. Colorado)

  Undergraduates

  I frequently work with undergraduates and I am always willing to supervise them on various projects of interest. I have written several papers with an undergrad as the first author. Recent undergrads: William Ouligian, Adam Usmanov, Jen Wang, Avyi Hill, Chloe Chen, Joe Landsittel

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  Current Projects

  This is a brief summary of some of the work that we do here. There are always tons of other projects!

  • Colon Motility

    This is a recent project with Kristen Smith-Williams where we are trying to understand the neural and muscular interactions which underly the spontaneous rhytmic contractions in the proximal colon. This combines detailed modeling and really awesome experiments.

  • Olfactory Navigation

    This is a large 29 investigator project where we are attempting to understand algorithms and neural circuits that animals use to find sources of odor. Odor plumes are complex objects, turbulent and intermittent, so the strategies animals use are diverse. Our group studies flies, mice, dogs, and humans tracking odors or finding spots. One of our group uses high speed filming to image odor plumes that we use to test algorithms.

  • Dynamics and phase resetting

    The phase resetting curve (PRC) tells us how the timing of inputs shift the timing of oscillators. The shapes of these curves are important both in coupled and in forced systems and play a critical role in synchronization. In neurons, there are many currents which are subject to modulation and these currents can have a strong affect on the shape and sensitivity of the PRC. Uncorrelated noise and coupling to other oscillators also alter the shape of the PRC. We use nonlinear dynamics and simulations to study how these curves are changed. This work is currently being done with Klaus Stiefel.

  • Pattern formation in neural systems

    This is fun stuff. I continue a long held interest in hallucinations and phosphenes as well as various types of pattern sensitive and reflex epilepsies. I am interested in mechanisms through which flickering light can induce geometric hallucinations as well as seizures in susceptible populations. Stewart Heitmann and I are starting to look at redoing some experiments on flicker. With Jay Pina, I am looking at how spatial inputs of certain spatial frequencies can induce oscillations in recurrent networks. We hope to explain certain flickering illusions and also why some pictures lead to visual discomfort.

  • Waves and persistent states in neural systems

    Due to the massive recurrent interactions between neurons, networks are able to sustain various types of persistent activity. By persistent, I mean activity that remains after a stimulus is removed. Working memory is believed to be such a state - a localized region of cortex remains active until the memory task is completed. We have several types of models involving combinations of multi-region interactions, multi-layer interactions and facilitation. This work has been with Mark Bodner; we are currently investigating the relationship between gamma rhythms and working memory. With David van Mannen, we have begun to explore the transition to clustering in gamma oscillations by looking at a particular set of maps.

    Another type of persistent activity comes in the form of propagating waves. These are observed in brain slices, cell cultures, and in vivo. We use spatial networks of neurons and singular perturbation theory to study propagation of activity in one- and two-dimensions. Jeremy Harris and I are looking at Discontinuous neural field models in order to study the transition from waves to fronts. The nature of the nonlinearities requires us to delicately handle the transistions across the discontinuities. We employ Filippov methods to resolve various bifurcations that can occur.

  • Other nonlinear dynamics models

    . With Jeff Dunworth, we are exploring the dynamics of small swarms and how they interact with a predator. We have found a number of interesting bifurcations as parameters such as the differential attractiveness of a specific prey animal changes. With Youngmin Park, we are looking at systems of oscillators that have both weak and slow interactions. We look at how a slowly changing environment can change the fast interactions between two oscillators by dynamically changing their PRCs.

  • Modeling the inflammatory response

    Pathogens, damage, and other insults to the body can result in inflammation which can sometimes be worse than the original insult. We work closely with several people at UPMC (Gilles Clermont, Yoram Vodovotz) developing models for the signalling pathways and responses of the innate immune system. We have applied these models to influenza, malaria, lung inflammation, necrotizing enterocolitis, and multiple organ dysfunction syndrome. We have recently developed a comprehensive model for pneumonia that is able to explain data from many different strains of mice as well as different strains of bacteria. This is work with David Swigon and Ericka Mochan. With Glenn Young and Jon Rubin, we are looking at how Salmonella is able to maximize its ability to invade the gut by exploiting the host immune system.