Robert G. Smith, Ph.D

faculty photo
Research Associate Professor of Neuroscience
Department: Neuroscience
Graduate Group Affiliations

Contact information
Department of Neuroscience
Rm 123, Anatomy-Chemistry Bldg /6058
University of PA School of Medicine
422 Curie Blvd.
Philadelphia, PA 19104
Office: 215-573-3211
- (Biology)
Haverford College, 1971.
University of Pennsylvania, College of General Studies, 1982.
Ph.D. (Neuroscience)
University of Pennsylvania, 1989.
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Description of Research Expertise

RESEARCH INTERESTS: Understanding how the structure, biophysical properties, and synaptic connections of a neuron influence its signal processing function within the surrounding neural circuit.

RESEARCH TECHNIQUES: Analysis of the role of synaptic and biophyical properties, morphology, and noise in a neural circuit's performance. Electrophysiological recordings. Computer simulation of neural circuitry. Ideal observer analysis of neural circuit performance.

RESEARCH SUMMARY: My laboratory studies how retinal circuitry processes visual signals. We analyze what is known about a circuit, construct a biophysically realistic model of it, and through simulation attempt to reconcile the circuit's known physiological properties with the function of its neural components. This allows us to suggest a functional interpretation for biophysical features such as dendritic branching, density of voltage-gated membrane channels, and specific location, strength, and properties of synaptic inputs. Including the noise properties of membrane channels and synaptic vesicle release, we generate realistic noise properties that we compare directly with recordings from live neurons. We currently study 4 circuits: 1) the cone photoreceptor to horizontal cell network, 2) the pathway from rod photoreceptors to ganglion cells used during dark adaptation, 3) the brisk-transient (alpha) ganglion cell, its spike generator, and its presynaptic circuitry, and 4) the direction-selective ganglion cell and the starburst amacrine network that shapes its responses.

Description of Other Expertise

Programming skill in the C and C++ programming languages, numerical integration. Analog and digital electronics design.

Selected Publications

Borghuis BG, Ratliff CP, Smith RG: Impact of light-adaptive mechanisms on mammalian retinal visual encoding at high light levels. J Neurophysiol 119(4): 1437-1449, December 2017 Notes: doi: 10.1152/jn.00682.2017

Howlett MH, Smith RG, Kamermans M: A novel mechanism of cone photoreceptor adaptation. PLoS biology 15(4): e2001210, April 2017 Notes: doi: 10.1371/journal.pbio.2001210.

Percival KA, Venkataramani S, Smith RG, Taylor WR: Directional Excitatory Input to Direction-Selective Ganglion Cells in the Rabbit Retina. J. Comp. Neurol March 2017 Notes: doi: 10.1002/cne.24207 [Epub ahead of print]

Stincic T, Smith RG, Taylor WR: Time-course of EPSCs in On-type starburst amacrine cells in mouse retina is independent of dendritic location. J. Physiol 594: 5685-5694, Oct 2016 Notes: doi:10.1113/jp272384.

Ding H, Smith RG, Poleg-Polsky A, Diamond JS, Briggman KL.: Species-specific wiring for direction selectivity in the mammalian retina. Nature 535: 105-110, July 2016 Notes: doi: 10.1038/nature18609.

Lipin MY, Taylor WR, Smith RG: Inhibitory input to the direction-selective ganglion cell is saturated at low contrast. J Neurophysiol 114(2): 927-941, August 2015 Notes: doi: 10.1152/jn.00413.2015.

Trenholm S, McLaughlin AJ, Schwab DJ, Turner MH, Smith RG, Rieke F, Awatramani GB. : Nonlinear dendritic integration of electrical and chemical synaptic inputs drives fine-scale correlations. Nat Neurosci 17(12): 1759-1766, December 2014 Notes: doi: 10.1038/nn.3851.

Puthussery T, Venkataramani S, Gayet-Primo J, Smith RG, Taylor WR: NaV1.1 Channels in Axon Initial Segments of Bipolar Cells Augment Input to Magnocellular Visual Pathways in the Primate Retina. J Neurosci. 33(41): 16045-16059, October 2013.

Nikonov S, Lyubarsky A, Fina M, Nikonova E, Sengupta A, Chinniah C, Ding X-Q, Smith R, Pugh E, Vardi N, Dhingra A. : Cones respond to light in the absence of transducin Beta3 subunit. J. Neurosci 33: 5182-5194, March 2013 Notes: doi: 10.1523/jneurosci.5204-12.2013.

Abbas SY, Hamade KC, Yang EJ, Nawy S, Smith RG, Pettit DL: Directional Summation in non-Direction Selective Retinal Ganglion Cells. PLoS Comput Biol 9(3): e1002969, March 2013 Notes: doi:10.1371/journal.pcbi.1002969.

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Last updated: 04/06/2018
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