University of Virginia Health System

Previous lab members

Jessica Risner, Ph.D.
Neuroscience Graduate Student

I received my B.S. in both Biology and Psychology from Heidelberg College in 2001, and in 2007 I received my doctorate from the Department of Neuroscience at the University of Virginia. I completed my thesis work in Jeff Holt's lab where I studied the vestibular ganglion neurons (VGNs) in the inner ear. I used electrophysiology to characterize the intrinsic firing properties of VGNs and have shown that the diverse firing properties observed in these neurons were due in part to the expression of a heterogeneous population of potassium conductances. Using various molecular, pharmacological and electrophysiological techniques, I have also presented evidence for potential molecular correlates for the potassium conductances shown to influence the properties of VGNs. I am currently working as a post-doc in Jeff Holt's lab, and am particularly interested in the KCNQ family of potassium channels. My thesis work established a role for KCNQ channels in VGN function. I currently utilize a variety of techniques including electrophysiology, pharmacology, quantitative RT-PCR, immunohistochemistry and in order to investigate how the members of the KCNQ family of potassium channels contribute to the function of VGNs. 

Chris Magnus
Laboratory Research Scientist

I have a B.Sc. in Biology from the University of Aberdeen, Scotland and an M.Sc. in Biomolecular Organization from Birkbeck College, London. I have not been working in hearing research for long, but I have nearly thirty years of experience as a lab technician, and nearly twenty years of experience in electrophysiology. I have worked on many preparations using the patch clamp technique, fluorescent ion indicators and flash photolysis. Much of this work was done with David Ogden in the Neurophysiology Department of the MRC NIMR, at Mill Hill, London.

Since moving to the USA in 2003 I have worked on GABA receptors with Steve Moss at Penn, and most recently with Jeff Corwin here at UVA, on the developmental regulation of inner ear hair cells in wound repair.  I moved to Jeff Holt's lab in September of 2006 where I am learning more about hair cell physiology every day. As well as making recordings from native and genetically modified hair cells I am learning the molecular techniques involved in modifying genes and incorporating them into viruses that will allow us to express proteins of interest in hair cells.  I also help with the running of the lab, liaising with various departments and offices around UVA, and generally trying to ease the administrative load on senior lab members to allow them more time for research. 

Eric Stauffer
Neuroscience Graduate Student

I received my B.S. in Neuroscience from Lafayette College, where, as an undergraduate researcher, I used genetic and electrophysiological methods to test the efficacy of anticonvulsant drugs in a drosophila model of epilepsy.  I am currently a PhD candidate in the Neuroscience Graduate Program at UVa.  Under the direction of my advisor, Jeff Holt, I study mechanotransduction, the process by which the sensory hair cells of the inner ear convert mechanical movements into electrical signals.  I move the hair bundles very small distances (<1 µm) and record the resulting mechanotransduction currents using the whole-cell technique.  Specifically, I am examining the phenomenon of adaptation within these hair cells, whereby the magnitude of the mechanotransduction currents decrease over time in the presence of constant stimuli. Along with our collaborators, we have utilized chemical-genetic and electrophysiological methods to demonstrate that Myosoin Ic participates in adaptation in vestibular hair cells.  My current work is focused on characterizing the properties of mechanotransduction and adaptation in auditory hair cells.

Email:      eas6v@virginia.edu

  Katie Barletta

Graduate Student, Medical Scientist Training Program

I worked in the Holt lab during the summer of 2006 for an MD-PhD rotation.  For my project, I imaged individual mouse cochlear hair cell stereocilia using confocal and 2-photon laser scanning microscopy.  I was interested to use FM and calcium sensitive dyes as an assay for functional mechanotransduction.

Email: keb3t@virginia.edu



David Abraham, Ph.D.

Post-doctoral Fellow

I am from The Netherlands where I did my undergraduate study at Utrecht University.  For my masters degree I used electrophysiology and pharmacology to characterize the subunit composition of nicotinic acetylcholine receptors. I enjoyed using molecular and electrophysiological techniques to study channel proteins in the cell membrane.  In 1996 I went to Sweden to do my PhD at Lund University where I started working in the pheromone group to construct a DNA based phylogeny for the subfamilies of Geometridae moths. Later I returned to my initial interests and recorded from single sensilla hairs on moth antennae.  I joined the Holt lab in July 2002 and am now involved in the identification, cloning and expression of potassium channels from the inner ear, particularly those involved in inherited deafness.  I use molecular techniques and electrophysiology to study the function of wild type and mutant potassium channels.

Email: da2s@virginia.edu

Holly Eppard

Lab Technician

I came to Jeff Holt's lab to work in September of 2003 after graduating earlier in May with a B.S. in Biology from Virginia Tech.   In addition to general lab manager responsibilities, I am involved with various aspects of the research  here in the Holt lab.  I assist with the generation of recombinant adenoviral vectors, as well as some of the molecular biology work and immuno-staining experiments.

 

Chuck Fletcher, M.D.

Otolaryngology Resident

I am a surgical resident physician in the Department of Otolaryngology Head & Neck Surgery. Our department gives us the opportunity to participate in a four month research rotation. My work in Dr. Holt's lab is focused on developing an RNA interference technique to suppress gene expression in mammalian hair cells.

 

Holt/Géléoc Lab circa Fall 2003

From left to right: Jeff Holt, Gwen Géléoc, Holly Eppard, Eric Stauffer, Jessica Risner, Valeria Piazza (visiting student), David Abraham, and kids Emma and Sander.

Holt/Géléoc Lab circa Spring 2004

From left to right: Chuck Fletcher, Holly Eppard, Gwen Géléoc, David Abraham, Eric Stauffer, Jessica Risner, Jeff Holt, Jonathan Ashmore (visiting Professor).

 

Holt/Géléoc Lab circa Fall 2007

From left to right:  Jeff Holt, Gwen Géléoc, Andrea Lelli, Jessica Risner, Geoff Horwitz, Yukako Asai, Chris Magnus, Eric Stauffer

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