|AFFILIATIONS||Professor of Vision Science and Optometry
Dean of Optometry, 2001-2013
Neural Plasticity in human vision.
Amblyopia is a developmental disorder of spatial vision usually associated with the presence of strabismus, anisometropia or form deprivation early in life. It affects visual acuity, contrast sensitivity and position acuity. Amblyopia is clinically important because, aside from refractive error, it is the most frequent cause of vision loss in infants and young children; and amblyopia is of basic interest because it reflects the neural impairment which can occur when normal visual development is disrupted. Generally, treatment of amblyopia is only undertaken in infants and young children and it is frequently quite effective.
The focus of our research is on recovery of visual function in humans with amblyopia beyond the critical period. Our research, using perceptual learning and videogame play suggests that substantial neural plasticity may exist in the visual system of adults with amblyopia. Our long-range objectives are to understand the mechanisms that limit spatial vision in humans with amblyopia, with the ultimate goal of developing new approaches aimed at more effective treatment.
Levi, D.M., Harwerth, R.S. and Smith, E.L. Humans Deprived of Normal Binocular Vision Have Binocular Interactions Tuned to Size and Orientation, Science, 206, 852-854, 1979.
Levi, D.M., and Klein, S. Hyperacuity and Amblyopia. Nature, 298, 268-270, 1982.
Levi, D.M., Manny, R.E., Klein, S.A., and Steinman, S.B. Electrophysiological correlates of hyperacuity in the human visual cortex. Nature, 306, 468-470, 1983.
Levi, D.M., and Klein, S.A. Sampling in Spatial Vision. Nature, 320, 360-362, 1986.
Levi, D.M. & Polat U. Neural plasticity in adults with amblyopia. Proceedings of the National Academy of Sciences (PNAS), 93, 6830-6834, 1996.
Levi, D.M. Pattern perception at high velocities. Current Biology, 6, 1020-1024, 1996.
Levi, D.M., Sharma, V. and Klein, S.A. Feature integration in pattern perception. Proceedings of the National Academy of Sciences (PNAS), 94:11742-11746, 1997.
McGraw, P.V., Levi, D.M. & Whitaker. Spatial characteristics of the non-linear visual pathway revealed by positional adaptation. Nature Neuroscience, 2, 479-84, 1999.
Sharma, V., Levi, D.M. & Klein, S.A. Under-counting features and missing features: evidence for a high level deficit in strabismic amblyopia. Nature Neuroscience, 3, 496-501, 2000.
Yu, C. & Levi, D.M. Surround modulation in human vision unmasked by masking experiments. Nature Neuroscience, 3, 724-728, 2000.
Popple, A.V. & Levi, D.M. Amblyopes see true alignment where normal observers see illusory tilt. Proceedings of the National Academy of Sciences (PNAS), 97, 11667-72, 2000.
Levi, D.M. & Klein, S.A. Noise provides some new signals about the spatial vision of amblyopes. Journal of Neuroscience, 23, 2522-2566, 2003.
Li, R.W-H., Levi, D.M. & Klein, S.A. Perceptual learning improves efficiency by re-tuning the “template” for position discrimination. Nature Neuroscience, 7, 178-183, 2004.
Kuai, S-G., Zhang, J-Y., Klein, S.A. Levi, D.M. & Yu, C., The essential role of stimulus temporal patterning for enabling perceptual learning. Nature Neuroscience, 8, 1497-1499, 2005.
Neri, P., Luu J.Y. & Levi, D.M. Meaningful interactions can enhance visual discrimination of human agents. Nature Neuroscience, 9, 1186-1192, 2006.
Zhang, J.Y., Kuai, S.G., Xiao, L.Q., Klein, S.A., Levi, D.M. and Yu, C. Stimulus coding rules for perceptual learning. PLoS Biology, 6(8): e197, 2008. doi:10.1371/journal.pbio.0060197.
Xiao, L.Q., Zhang, J.Y., Wang, R., Klein, S.A., Levi, D.M. and Yu, C. Complete Transfer of Perceptual Learning across Retinal Locations Enabled by Double Training. Current Biology, 18, 1922-26, 2008.
Li, R.W., Klein, S.A. & Levi, D.M. Prolonged perceptual learning of positional acuity in adult amblyopia: perceptual template retuning dynamics. J Neurosci., 28, 14223-9. 2008.
Levi, D.M. & Li, R.W. Improving the performance of the amblyopic visual system. Philosophical Transactions of the Royal Society B, 364, 399-407, 2009.
Levi, D.M. & Carney T. Crowding in Peripheral Vision: Why Bigger Is Better. Current Biology, 1988-93, 2009.
Zhang, J.Y., Zhang, G.L., Xiao, L.Q., Klein, S.A., Levi, D.M. and Yu, C. Rule-based learning explains visual perceptual learning and its specificity and generalization. J. Neurosci., 30, 12323-28, 2010.
Bavelier, D., Levi, D.M., Li, R.W., Dan, Y & Hensch, T.K. Removing Brakes on Adult Brain Plasticity. From Molecular to Behavioral Interventions. J. Neurosci., 30, 14964-71, 2010.
Whitney, D. & Levi, D.M. Visual crowding: a fundamental limit on conscious perception and object recognition. Trends In Cognitive Sciences, 15, 160-168, 2011.
Li, R.W., Ngo, C., Nguyen, J. & Levi, D.M. Video game play induces plasticity in the visual system of adults with amblyopia. PLoS Biology, 9(8): e1001135, 2011.
Ding, J. & Levi, D.M. Recovery of stereopsis through perceptual learning in human adults with abnormal binocular vision. Proc Natl Acad Sci (U S A), 108(37):E733-41, 2011.
Kuai, S-G., Levi, D.M. & Kourtzi, Z. Learning optimizes decision templates in the human visual cortex. Current Biology, 23, 1799-1804, 2013.
Li, R.W., Ngo, C.V., & Levi, D.M. Relieving the Attentional Blink in the Amblyopic Brain with Video Games. Scientific Reports, 2015 Feb 26;5:8483. doi: 10.1038/srep08483.
Vedamurthy, I., Knill, D., Huang, S. J., Yung, A., Ding, J., Kwon, O., Bavelier, D. & Levi, D.M. Recovering stereo vision by squashing virtual bugs in a virtual reality environment. Philosophical Transactions of the Royal Society B, 2016. Jun 19; 371(1697). pii: 20150264. doi: 10.1098/rstb.2015.0264.
Yehezkel, O., Ding, J., Sterkin, A., Polat, U. & Levi, D.M. Binocular combination of stimulus orientation. R. Soc. open sci., 2016, 3: http://dx.doi.org/10.1098/rsos.160534