Laboratory of Robert G. Smith, PhD

Neural Simulation

Research Associate Professor
Department of Neuroscience
University of Pennsylvania
Rm 123, Anat-Chem Bldg. /6058
37th and Service Dr.
Philadelphia, PA 19104-6058

Member of the Institute for Neurological Sciences

rob<at>retina.anatomy.upenn.edu login

Click here to see the NeuronC User's Manual. Click here to receive the NeuronC distribution.

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

RESEARCH TECHNIQUES: Computer simulation of neural circuitry. Analysis of the role of morphology, synaptic connections and noise in a neural circuit's 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. By including the noise properties of membrane channels and synaptic vesicle release, we generate realistic noise properties that we compare directly with recordings from the live neurons. We are currently focussing on 3 circuits: 1) the cone photoreceptor to horizontal cell network, 2) the pathway from rod photoreceptors to ganglion cells used during dark adaptation and 3) the ganglion cell, its spike generator, and its presynaptic circuitry.

Click here for microcircuitry simulation projects:

Click here for more about me:

Other places down the hall.

  • Department of Neuroscience at the University of Pennsylvania.
  • Institute of Neurological Sciences
  • Department of Physiology
  • Department of Pharmacology
  • Department of Biochemistry and Biophysics

    Vision and Neuroscience web pages:

  • ARVO
  • Society for Neuroscience
  • Journal of Neuroscience
  • Neurosciences on the Internet
  • The Vision Science homepage
  • Andrew Stockman's Color & Vision Database
  • Helga Kolb's WebVision page, "The Neural Organization of the Vertebrate Retina"
  • Lance Hahn's retina stuff
  • Lance Hahn's home page.

    Other vision researchers at Penn with similar interests:

  • Michael Freed
  • Peter Sterling
  • Larry Palmer
  • Diego Contreras
  • Josh Gold
  • Leif Finkel
  • List of Penn Perception labs in various Schools at the University of Pennsylvania.

    Bibliography

    Refereed Papers:


    Borghuis BG, Ratliff CP, Smith RG, Sterling P, Balasubramanian V. (2008) Design of a neuronal array. J Neurosci 28:3178-3189.

    Yin L, Smith RG, Sterling P, Brainard DH (2006) Chromatic properties of horizontal and ganglion cell responses follow a dual gradient in cone opsin expression. J Neurosci 26:12351-12361.

    Dhingra NK, Freed, MA, Smith RG (2005) Voltage-gated sodium channels improve contrast sensitivity of a retinal ganglion cell. J Neurosci 25:8097-8103.

    Xu Y, Dhingra NK, Smith RG, Sterling P (2005) Sluggish and brisk ganglion cells detect contrast with similar sensitivity. J Neurophsiol 93:2388-2395.

    Berntson A, Smith RG, Taylor WR (2004) Postsynaptic calcium feedback between rods and rod bipolar cells in the mouse retina. Visual Neurosci 21:913-924.

    Berntson A, Smith RG, Taylor WR (2004) Transmission of single photon signals through a binary synapse in the mammalian retina. Visual Neurosci 21:693-702.

    Taylor WR, and Smith RG (2004) Transmission of scotopic signals from the rod to rod-bipolar cell in the mammalian retina. Vision Res. (2004) 44: 3269-3276.

    Tukker JJ, Taylor WR, and Smith, RG. (2004) Direction selectivity in a model of the starburst amacrine cell. Visual Neurosci. (2004)21: 611-625.

    Dhingra NK, and Smith RG (2004) Spike generator limits efficiency of information transfer in a retinal ganglion cell J. Neurosci. (2004) 24: 2914-2922.

    Freed, M.A., Smith, R.G., and Sterling, P. (2003) Timing of quantal release from the retinal bipolar terminal is regulated by a feedback circuit. Neuron, 38: 89-101.

    van Rossum, M.C.W., O'Brien, B., and Smith, R.G. (2003) Effects of noise on the spike timing precision of retinal ganglion cells. J. Neurophysiol. 89:2406-2419.

    Dhingra, N.K., Kao, Y.-H., Sterling, P., and Smith, R. (2003) Contrast treshold of a brisk-transient ganglion cell in vitro. J. Neurophysiol. 89:2360-2369.

    DeVries S, Qi X-F, Smith R, Makous W, and Sterling, P. (2002) Electrical coupling enhances contrast sensitivity of foveal cones. Current Biology 12:1900-1907.

    Hsu, A., Smith, R.G., Buchsbaum, G., and Sterling, P. (2000) Cost of coupling to trichomacy in foveal cones. J Optical Soc. Am. A 17:(3) 635-640.

    van Rossum, M.C.W., and Smith, R.G. (1998) Noise removal at the rod synapse. Visual Neurosci., 15: 809-821.

    Hsu, A., Tsukamoto, Y., Smith, R.G., and Sterling, P (1998) Functional architecture of primate cone and rod axons. Vision Research 38: 2539-2549.

    Vardi, N. and Smith, R.G. (1996) The AII amacrine array: coupling can increase correlated activity. Vision Res. 36: 3743-3757.

    Smith, R.G. (1995) Simulation of an anatomically-defined local circuit: the cone-horizontal cell network in cat retina. Visual Neurosci., 12: 545-561.

    Smith, R.G., and Vardi, N. (1995) Simulation of the AII amacrine cell in cat retina: Functional consequences of electrical coupling and regenerative membrane properties. Visual Neurosci., 12: 851-860.

    Hsu, A., and Smith, R.G. (1994) Simulating the foveal cone receptive field. In: Computation in Neurons and Neural Systems, Ed. by Frank H. Eeckman. Kluwer Academic Publishers, Boston.

    Smith, R.G. (1994) Measurement of simulation speed: its relation to simulation accuracy. In: Computation in Neurons and Neural Systems, Ed. by Frank H. Eeckman. Kluwer Academic Publishers, Boston.

    Freed, M.A., Smith, R.G., and Sterling, P. (1992) Computational model of the on-alpha ganglion cell receptive field based on bipolar cell circuitry. Proc. Nat. Acad. Sci. 89: 236-240.

    Smith, R.G.(1992) NeuronC: a computational language for investigating functional architecture of neural circuits. J. Neurosci. Meth 43: 83- 108.

    Sterling, P., Cohen, E., Smith, R.G., and Tsukamoto, Y. (1992) Retinal circuits for daylight: why ballplayers don't wear shades. In: Analysis and Modeling of Neural Systems, Ed. by Frank H. Eeckman. Kluwer Academic Publishers.

    Tsukamoto, Y., Smith, R.G., and Sterling, P. (1990) "Collective coding" of correlated cone signals in the retinal ganglion cell. Proc. Nat. Acat. Sci. 87: 1860-1864.

    Smith, R.G., and Sterling, P. (1990) Cone receptive field in cat retina computed from microcircuitry. Visual Neurosci. 5: 453-461.

    Sterling, P., Freed, M.A., and Smith, R.G. (1988) Functional architecture of the rod and cone circuits to the on-beta ganglion cell. J. Neurosci. 8:623- 642.

    Smith, R.G. (1987) Montage: a system for three-dimensional reconstruction by personal computer. J. Neurosci. Meth. 21:55-69.

    Sterling, P., Cohen, E., Freed, M.A., and Smith, R.G. (1987) Microcircuitry of the on-beta ganglion cell in daylight, twilight and starlight. Neurosci. Research, Suppl. 6, S269-S285.

    Freed, M.A., Smith, R.G., and Sterling, P. (1987) Functional architecture of the rod bipolar neuron in cat retina. J. Comp. Neurol. 266: 445-455.

    Smith, R.G., Freed, M.A., and Sterling, P. (1986) Microcircuitry of the dark-adapted cat retina: Functional architecture of the rod-cone network. J. Neurosci 6:3505-3517.

    Sterling, P., Freed, M.A., and Smith, R.G. (1986) Microcircuitry and functional architecture of the cat retina. Trends in Neurosci. 9:186-192.

    Kauffman, S.A., and Smith, R.G. (1986) Adaptive automata based on darwinian selection. Physica 22D:68-82.

    Chapters and Symposia proceedings:

    Smith RG (2008) Contributions of Horizontal Cells. In: Allan I. Basbaum, Akimichi Kaneko, Gordon M. Shepherd, and Gerald Westheimer (Editors) The Senses: A Comprehensive Reference, Vol 1, Vision I, Richard Masland, and Thomas D Albright, Eds. San Diego, Academic Press, p 348-350.

    Dhingra NK, Smith R, Sterling P (2003) Psychophysics to biophysics: how perception depends on circuits, synapses, and vesicles. In: A. Kaneko (Ed) The Neural Basis of Early Vision. Keio University International symposia for Life Sciences and Medicine, Springer-Verlag, Tokyo, Vol. 11.

    Smith, R.G. (2002) Retina. In: Michael A. Arbib (Ed.): The Handbook of Brain Theory and Neural Networks (second ed). MIT Press.

    Smith RG, Dhingra NK, Kao YH, Sterling P (2001) How efficiently a ganglion cell codes the visual signal. Proc. IEEE Eng. Med. Biol. Soc., IEEE, Piscataway, NJ, Vol. 1, pp 663-665.

    Sterling, P., Smith, R.G., Rao, R., and Vardi, N. (1995) Functional architecture of mammalian outer retina and bipolar cells. In: Archer S., Djamgoz, M.B.A., and Vallerga, S. (Eds.): Neurobiology of the vertebrate outer retina. Chapman & Hall, Ltd., London.


    Alternative Media:

    Smith, R.G. Neuron-C - A simulation language for testing hypotheses about neural performance.

  • Described at: http://retina.anatomy.upenn.edu/~rob/neuronc.html
  • Available at: ftp://retina.anatomy.upenn.edu/pub/nc.tgz

    Some fun & useful pointers:

    Useful information:

    Connect to Nature:

    Maps & Phila info:


    Last updated 2008/05/14

    Rob Smith