This page presents a survey of my work before I started studying crossmodal sensory integration. For current work, please look at the lab’s Research page.
In the lab of Bill Kristan at UCSD, I combined electrophysiology and voltage-sensitive dye imaging to study the neuronal basis of motor behavior associated with mating in the medicinal leech Hirudo verbana. This became possible thanks to the discovery of the remarkable effects of conopressin, a vasopressin/oxytocin analog isolated from the venom of the sea snail Conus imperialis. When injected into adult leeches, conopressin evoked behavior that looks just like motor behaviors observed during mating. The evoked behavior was very robust, and persists even in the isolated nerve cord. Thus, conopressin offered us a novel and very exciting opportunity to study the activity of the nervous system that drives mating, circumventing the unresolved challenge of electrophysiologically recording directly from leeches as they mate.
As a graduate student at Caltech with Jerry Pine and Steve Potter (at Georgia Tech), I grew cultures of rat cortical neurons on multi-electrode arrays, and studied the networks they formed. We were interested in their spontaneous activity patterns, as well as in the possibility of modifying those patterns using electrical stimulation. We found that their spontaneous activity was extremely rich, and consisted largely of network-spanning bursts of spikes. We hypothesized that these bursts were anomalous, since in healthy animals network-spanning bursts only occur during a brief developmental period. Persistence of bursting could be a result of lack of afferents into the culture, and may be related to epilepsy. By sprinkling in electrical stimulation through many electrodes, we found that we could quiet these bursts. Burst control persisted for as long as electrical stimuli were applied. Achieving a permanent change in network activity patterns through long-term plasticity turned out to be difficult, but initial results indicate that control of plasticity is facilitated by burst quieting.
After completing my degree in theoretical physics, I spent a year at the Math Department of King’s College, London, learning about information theory and neural networks. In particular, I studied information geometry, an elegant framework that describes information and probability theory in terms of Riemannian geometry (which is the mathematics underlying general relativity), and how it applies to neural networks.
Research Professor and Director of the Neurotechnology Institute: Division of Biology and Biological Engineering, California Institute of Technology, 2016–
Assistant Professor: Department of Biological Sciences, University of Cincinnati, 2013–2016
Senior Research Fellow: Lab of Markus Meister, California Institute of Technology, 2012–2013
Broad Senior Research Fellow in Brain Circuitry: California Institute of Technology, 2008–2012
Postdoc: With Bill Kristan at the University of California, San Diego, 2005–2008
PhD (Physics): California Institute of Technology, 2006
MSc (Information Processing and Neural Networks): King’s College London, 1998
MSc (Theoretical Physics): University of Amsterdam (cum laude), 1997
Burroughs Wellcome Fund: Career Award at the Scientific Interface, 2009
Burroughs Wellcome Fund: Fellowship in Computational Molecular Biology, 2000
King’s College London: Prize for Best Overall Performance in the IP/NN MSc Program, 1998
Netherlands Organization for Scientific Research: Talent Program Fellowship for Study Abroad, 1997