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Robert ShapleyVisual physiology and perception
After graduating from Harvard, concentrating in Chemistry and Physics, I obtained a PhD degree from Rockefeller University in neurophysiology and biophysics under the supervision of H.K. Hartline. Hartline received the Nobel Prize for Medicine and Physiology a year after I arrived in his lab. My PhD thesis was about the random firing rate of eccentric cells in the eye of the horseshoe crab, Limulus. After the PhD I went to Northwestern University with a Helen Hay Whitney Postdoctoral Fellowship to work with Christina Enroth-Cugell on cat retinal ganglion cells. The second half of the Whitney Fellowship was spent at Cambridge University in the labs of Fergus Campbell and John Robson, studying with David Tolhurst how humans detect edges. In 1972 I returned to Rockefeller as Assistant Professor, and then Associate Professor, investigating parallel processing of visual signals in the retinas of many different vertebrates: cats, eels, frogs, monkeys. Worked at Rockefeller with Shaul Hochstein, Jonathan Victor, Norman Milkman, Ehud Kaplan, Yuen Tat So, Jim Gordon, Keith Purpura, and Clay Reid, among others in the Biophysics Laboratory. One happy memory from those days is when I received a MacArthur Fellowship, in 1986. Moved on in 1987 to the NYU Center for Neural Science where I have studied the primary visual cortex (V1) and visual perception with colleagues Mike Hawken, Dario Ringach, Michael Sceniak, Isabelle Mareschal, Elizabeth Johnson, Andy Henrie, Dajun Xing and Chun-I Yeh. Our ultimate goals are to relate neuronal activity in the visual cortex to visual perception and also to use V1 as a model system that reveals fundamental processes of the cerebral cortex. To achieve the second goal I helped construct several different large-scale cortical models with Courant Institute Professors David McLaughlin and Michael Shelley with postdocs Jim Wielaard, Louis Tao, Wei Zhu, and with I-Chun Lin and Dajun Xing.
More recently, Courant Professor Lai Sang Young and I, together with Logan Chariker, built a new, more realistic model of V1. We are using the new model to understand synchrony and the nonlinear dynamics of V1, orientation and spatial frequency selectivity, and contrast response. The figure shows membrane potential, membrane currents and conductances in a model cortical cell and illustrates how inhibitory and excitatory synaptic currents are balanced almost at all times except when excitation breaks free to evoke spikes.
Another line of present research is about color perception and color's representation in the human visual cortex. Hunter College Professor Jim Gordon, Dr. Valerie Nunez and I found that the cVEP, the color visual evoked potential, and perception have a very similar dependence on the spatial pattern of color. The figure shows an important result that perceived color of a color pattern is greater than for large uniform region of color, implying that color perception depends on the activity of double-opponent cells in V1 cortex.
Complete CV and bibliography [ pdf ]Selected Past and Recent PublicationsShapley R and Victor JD (1978) The effect of contrast on the transfer properties of cat retinal ganglion cells, J.Physiol 285, 275-298 [ pdf ] Shapley R and Enroth-Cugell C (1984) Visual Adaptation and Retinal Gain Controls, Progress in Retinal Research, vol. 3, ed. N. Osborne and G. Chader, Pergamon, p. 263-346 [ pdf ] Shapley R and Perry VH (1986) Cat and monkey retinal ganglion cells and their visual functional roles Trends in Neurosciences 9, 229-235 [ pdf ] Ringach D Hawken M and Shapley R (1997) Dynamics of orientation tuning in macaque primary visual cortex. Nature 387, 281-284. [ pdf ] Sceniak MP Ringach DL Hawken MJ, and Shapley R (1999) Contrast's effect on spatial summation by macaque V1 neurons. Nature Neuroscience 2, 733-739 [ pdf ] Henrie JA, Shapley R. (2005) LFP power spectra in V1 cortex: the graded effect of stimulus contrast J Neurophysiol 94:479-90 [ pdf ] Yeh CI, Xing D, Williams PE, Shapley RM. (2009) Stimulus ensemble and cortical layer determine V1 spatial receptive fields. Proc Natl Acad Sci U S A. 106:14652-7. [ pdf ] Xing D, Yeh CI, Shapley RM (2010) Generation of Black-Dominant Responses in V1 Cortex. J Neurosci. 30:13504-13512. [ pdf ] Burns SP, Xing D, Shelley MJ, Shapley RM (2011) Is gamma-band activity in the local field potential of V1 cortex a "clock" or filtered noise?. J Neurosci. 31:9658-9564 [ pdf ] Shapley R, Hawken, MJ (2011) Color in the Cortex:single and double-opponent cells. Vision Research 51(7):701-17 [ pdf ] Xing D, Ouni A, Chen S, Sahmoud H,Gordon J, Shapley RM (2015) Brightness-color interactions in human early visual cortex. J Neurosci. 35:2226-32. [ pdf ] Chariker L, Shapley R, Young LS (2016) Orientation Selectivity from Very Sparse LGN Inputs in a Comprehensive Model of Macaque V1 Cortex. J Neurosci. 36:12368-84. [ pdf ] Shapley RM (2019) Physiology of Color Vision in Primates. Oxford Research Encyclopedia of Neuroscience DOI: 10.1093/acrefore/9780190264086.013.74 1-37 [ pdf ] |
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