Noga Vardi, Ph.D

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Adjunct Professor of Neuroscience
Department: Neuroscience

Contact information
123A Anatomy-Chemistry Building
Department of Neuroscience
Perelman School of Medicine
University of Pennsylvania
Philadelphia, PA 19104-6058
Office: 215-898-4520
Fax: 215-898-6228
Education:
B.Sc (Biology)
Hebrew University, Jerusalem, 1974.
(Courses toward M.A in Neuroscience)
Hebrew University, Jerusalem, 1975.
Ph.D. (Maj. Neurobiology and Behavior, Min. Elec. Eng)
Cornell University, 1981.
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Description of Research Expertise

RESEARCH INTERESTS
Retinal processing with focus on chemical architecture and principles of signal processing.

RESEARCH TECHNIQUES
Electrophysiology; immunocytochemistry; electroretinogram; dye injection; electron microscopy; molecular biology; yeast two hybrid systems; computer simulation; live two photon imaging.

RESEARCH SUMMARY
General Description: The retina provides an excellent model system for signal processing because the input (visual image) is well defined, the output (ganglion cell responses) has been thoroughly studied, and circuits of parallel pathways from photoreceptor to ganglion cells were described better than any other neural system. To reliably transfer the signal from photoreceptor to ganglion cells through these pathways under a large range of luminances the retina employs gain control and noise removal mechanisms. Gain is adjusted by GABAergic and glycinergic feedback circuits in the outer and inner plexiform layers. These circuits tune photoreceptor, bipolar and ganglion cells' responses by averaging and feeding back ambient light information. A major focus of the lab is the pathway of the ON bipolar cells and their signaling cascade. The ON bipolar cells express the metabotropic glutamate receptor mGluR6. This receptor activates Go, and this eventually closes the nonspecific TRPM1 cation channel. We are studying the events that occur downstream of Go and how they are modulated. Whether Go activates directly the channel, or through a second messenger is important because the manner of activation determines the gain and the adaptation of these cells. In particular, both mGluR6 and Go are present in both rod and cone bipolar cells, but the two classes have different function (slow for night vision vs. fast for day vision), and one expects the cascade to differ in order to match and optimize the function. In addition, we study how the whole complex of the cascade is trafficked to the dendritic tip, and how a lack of a certain element destabilizes the complex and the synapse. Knowledge of this cascade is essential for understanding and treating night blindness.
A second project concerns cone bipolar cell types; there exist about 5 types that are thought to conduct different temporal bandwidth. Nothing is known about their precise light properties and how they achieve their differences. We study this by calcium imaging of ON bipolar cells. Such understanding will shed light on day light vision.

Selected Publications

Anuradha Dhingra, Meisheng Jiang, Tian-Li Wang, Arkady Lyubarsky, Andrey Savchenko. Tehilla Bar-Yehuda, Peter Sterling, Lutz Birnbaumer, and Noga Vardi: Ligh response of retinal ON bipolar cells requires a specific splice variant of Gao. Journal of Neuroscience 22: 4878-84, Nov 2002.

Gincel Dan, Vardi Noga, Shoshan-Barmatz Varda: Retinal voltage-dependent anion channel: characterization and cellular localization. Investigative ophthalmology & visual science 43(7): 2097-104, Jul 2002.

Dhingra Anuradha, Sulaiman Pyroja, Xu Ying, Fina Marie E, Veh Rüdiger W, Vardi Noga: Probing neurochemical structure and function of retinal ON bipolar cells with a transgenic mouse. The Journal of comparative neurology 510(5): 484-96, Oct 2008.

Xu Ying, Sulaiman Pyroja, Feddersen Rod M, Liu Jian, Smith Robert G, Vardi Noga: Retinal ON bipolar cells express a new PCP2 splice variant that accelerates the light response. The Journal of neuroscience : the official journal of the Society for Neuroscience 28(36): 8873-84, Sep 2008.

Sulaiman Pyroja, Fina Marie, Feddersen Rod, Vardi Noga: Ret-PCP2 colocalizes with protein kinase C in a subset of primate ON cone bipolar cells. The Journal of comparative neurology 518(7): 1098-112, Apr 2010.

Xu Y, Dhingra A, Fina ME, Koike C, Furukawa T, Vardi N.: mGluR6 deletion renders the TRPM1 channel in retina inactive. J Neurophysiol. 107(3): 948-57, Feb 2012.

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Last updated: 09/19/2014
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