|AFFILIATIONS||Professor of Vision Science and Optometry|
High resolution neuroscience in humans
Single Cone Psychophysics. We are using Austin Roorda’s adaptive optics scanning laser ophthalmoscope (AOSLO) for human psychophysics (for details go to Roorda’s information). The AOSLO has the capability of stimulating individual cones repeatedly, with the ability to go to the same cones over years. AOSLO’s unique capabilities enable us to learn about fine-grained spatio-temporal-chromatic nonlinear visual processing that was previously not available for investigation. Only three such instruments are presently available, one at UCSF for clinical research, one in Alabama for primate research and the one at Berkeley used for normal humans. The full single cone capability of these instruments has only been realized in 2012, so this collaborative research is in its exciting pioneering stage.
Modeling of Spatial Vision. The visual system is assumed to consist of an enormous number of spatial filters with different positions, sizes, orientations and bandwidths. These filters are arranged in sequential stages with nonlinear interactions between and within the stages. In our laboratory, we do psychophysical experiments to learn about the multiple stages of visual processing. Our recent research has explored the role of perceptual learning, attention and binocular interactions.
Nonlinear Systems Analysis with Application to Localizing VEP Sources. The use of fMRI and MRI scans for imaging brain activity has created much excitement among brain researchers. We have developed a new approach that combines nonlinear analysis, MRI, fMRI and the visual evoked potential (VEP) should reveals the underlying neural generators of visual cortex with a temporal resolution 100-1000 times better than is possible with fMRI.
Dandekar S, Ding J, Privitera C, Carney T, Klein SA. (2012) The fixation and saccade p3. PLoS One. 7(11):e48761. [PDF]
Dandekar S, Privitera C, Carney T, Klein SA (2012) Neural saccadic response estimation during natural viewing. J Neurophysiol. 107(6):1776-90. [PDF]
Wang R, Zhang JY, Klein SA, Levi DM, Yu C. (2012) Task relevancy and demand modulate double-training enabled transfer of perceptual learning.Vis Res. 61:33-8. [PDF]
Privitera CM, Renninger LW, Carney T, Klein S, Aguilar M. (2010) Pupil dilation during visual target detection. J Vis. 10(10):3. [PDF]
Zhang JY, Zhang GL, Xiao LQ, Klein SA, Levi DM, Yu C. (2010) Rule-based learning explains visual perceptual learning and its specificity and transfer. J Neurosci. 30(37):12323-8. [PDF]
Ales J, Carney T, Klein SA. (2010) The folding fingerprint of visual cortex reveals the timing of human V1 and V2. Neuroimage. 49(3):2494-502. [PDF]
Levi DM, Carney T. (2009) Crowding in peripheral vision: why bigger is better. Curr Biol. 19(23):1988-93. [PDF]
Klein SA. (2009) “Eye of Origin” in Bayne T, Cleeremans A, Wilken P. The Oxford Companion to Consciousness. Oxford: Oxford University Press. [PDF]
Klein SA, Levi DM. (2009) Stochastic model for detection of signals in noise.J Opt Soc Am A Opt Image Sci Vis. 26(11):B110-26. [PDF]
Zhang T, Xiao LQ, Klein SA, Levi DM, Yu C. (2009) Decoupling location specificity from perceptual learning of orientation discrimination. Vision Res. 50(4):368-74. [PDF]
Qian M, Aguilar M, Zachery KN, Privitera C, Klein S, Carney T, Nolte LW. (2009) Decision-level fusion of EEG and pupil features for single-trial visual detection analysis. IEEE Trans Biomed Eng. 56(7):1929-37. [PDF]
Liu L, Klein SA, Xue F, Zhang JY, Yu C. (2009) Using geometric moments to explain human letter recognition near the acuity limit. J Vis. 9(1):26.1-18. [PDF]
Li RW, Klein SA, Levi DM. (2008) Prolonged perceptual learning of positional acuity in adult amblyopia: perceptual template retuning dynamics. J Neurosci. 28(52):14223-9. [PDF]
Xiao LQ, Zhang JY, Wang R, Klein SA, Levi DM, Yu C. (2008) Complete transfer of perceptual learning across retinal locations enabled by double training. Curr Biol. 18(24):1922-6. [PDF]
Zhang JY, Kuai SG, Xiao LQ, Klein SA, Levi DM, Yu C. (2008) Stimulus coding rules for perceptual learning. PloS Biol, 6(8):e197. [PDF]
Levi DM, Klein SA, Chen I. (2008) What limits performance in the amblyopic visual system: seeing signals in noise with an amblyopic brain. J Vis.8(4):1.1-23. [PDF]
Privitera C, Renninger L, Carney T, Klein SA, Aguilar M (2008) The pupil dilation response to visual detection. Human Vision and Electronic Imaging XII, Bernice Rogowitz, Thrasyvoulos Pappas, Scott Daly Editors SPIE 6806. [PDF]
Carney T, Ales J & Klein SA (2008) Combining MRI and VEP imaging to isolate the temporal response of visual cortical areas. Human Vision and Electronic Imaging XII, Bernice Rogowitz, Thrasyvoulos Pappas, Scott Daly Editors SPIE 6806. [PDF]