本实验室主要运用心理物理学方法研究人类视觉过程以及相关的眼科与视光学临床应用。近年的主要研究兴趣在于知觉学习的心理物理学与脑机制，以及字符（汉字）识别的视觉机制和轮廓整合过程。

知觉学习：

知觉学习指通过训练来提高感觉辨别能力的过程，被认为是在系统水平上发映了大脑的神经可塑性。近二十年来有大量的关于知觉学习的心理物理学，神经生理学，脑成像和计算神经科学的研究成果出现，是认知神经科学的一个重要研究领域。

我们的主要研究贡献在于用创新性实验范式，挑战了视知觉学习研究关于视网膜位置特异性与朝向特异性的的基本假设以及基于这些假设的各种知觉学习理论 (Current Biology, 2008; J Neuroscience, 2010)。知觉学习因其位置与朝向特异性类似于视觉初级皮层(V1)的网膜拓扑对应特性和朝向选择性，长期以来被认为反映了V1神经可塑性。但我们的研究证明知觉学习可以在不同网膜位置和朝向间完全迁移，位置与朝向特异性实际上是特定训练方式的结果，而和知觉学习并无关系。这些发现还表明知觉学习是一个超出视觉皮层的高级认知过程。基于这些重要研究发现，我们初步提出了一个基于规则的知觉学习理论 (Rule-based perceptual learning theory) 来解释知觉学习及其特异性与迁移的脑机制 (J Neuroscience, 2010)。目前我们进行的大量实验皆在于验证和发展这一理论，以及研究这一理论在临床视觉训练中的意义。

我们还发现对多个视觉刺激的知觉学习依赖于刺激的时间模式编码, 当刺激的时间模式固定时才能获得好的学习效应,而随机时间模式无法产生学习效果（Nature Neuroscience, 2005）。此外大脑学习多个刺激时，需要借助刺激的次序和节奏信息，或者刺激的概念或语义标签，来帮助大脑识别各感觉刺激（PLoS Biology, 2008）。据此提出的刺激标签模型 (Stimulus tagging model) 认为，大脑同时学习多个刺激时，需要在一定的时间窗口内通过刺激的固有次序和节奏, 或者在概念或语义水平上，对各刺激进行识别，从而帮助大脑将注意指向相应的神经过程，以在高级决策单元和各感觉刺激输入之间建立相应的功能连接来实现知觉学习。

字符（汉字）识别：

我们发现笔划数对汉字识别的大小阈限只有有限的影响，而刺激间的几何矩差能较好地模拟根据识别错误建立的混淆矩阵。这些结果证明汉字识别阈限主要受刺 激的总体特征所决定, 而较少受细节特征的影响（IOVS, 2007；Journal of Vision, 2009）。我们还对汉字识别在周边视觉的表现及相关的视觉拥挤现象做了研究，发现了周边视觉汉字识别存在着内部拥挤现象，以及top-down因素对视觉拥挤的影响（Vision Research, 2009）。最新的研究则发现，相当成分的视觉信息在视觉拥挤过程的影响下并没有如当前理论所假设的丧失在识别过程中，而是在视觉记忆或注意过程中出现了错位。这一发现为视觉拥挤现象提供了新的认识（Journal of Vision, 2012）。

轮廓整合：

我们在对周边视觉轮廓整合的研究中, 发现在减少刺激不确定性后, 周边视觉中的轮廓整合能力与中心视觉相当 (J Vision, 2006)。我们最近的研究兴趣在轮廓整合的时间与空间特征 （VSS09, VSS10)。

英文论著

Ju, N. S., Guan, S. C., Tang, S. M., & Yu, C. (2022). Macaque V1 responses to 2nd-order contrast-modulated stimuli and the possible subcortical and cortical contributions. Progress in Neurobiology, 102315.

Xiong, Y. Z., Guan, S. C., & Yu, C. (2022). A supramodal and conceptual representation of subsecond time revealed with perceptual learning of temporal interval discrimination. Scientific Reports, 12(1), 1-9.

Guan, S. C., Ju, N. S., Tao, L., Tang, S. M., & Yu, C. (2021) Functional organization of spatial frequency tuning in macaque V1 revealed with two-photon calcium imaging. Progress in Neurobiology, 205, 102120.

Hu, D. Z., Wen, K., Chen, L.H., & Yu, C. (2021) Perceptual learning evidence for supramodal representation of stimulus orientation at a conceptual level, Vision Research, 187, 120-128.

Ju, N. S., Guan, S. C., Tao, L., Tang, S. M., & Yu, C. (2021) Orientation tuning and end-stopping in macaque V1 studied with two-photon calcium imaging. Cerebral Cortex, 31, 2085-97.

Xie, X. Y., Zhao, X. N., & Yu, C. (2020). Perceptual learning of motion direction discrimination: Location specificity and the uncertain roles of dorsal and ventral areas. Vision Researh, 175, 51-57

Xie, X. Y., Liu, L. & Yu, C. (2020). A new perceptual training strategy to improve vision impaired by central vision loss. Vision Research, 174, 69-76.

Guan, S. C., Zhang, S. H., Zhang, Y. C., Tang, S. M., & Yu, C. (2020). Plaid detectors in macaque V1 revealed by two-photon imaging. Current Biology, 30, 934-940.

Xie, X. Y., & Yu, C. (2020). A new format of perceptual learning based on evidence abstraction from multiple stimuli, Journal of Vision, 20, 5.

Xiong, Y. Z., Tang, D. L., Zhang, Y. X., & Yu, C. (2020). Complete cross-frequency transfer of tone frequency learning after double training. Journal of Experimental Psychology: General, 149(1):94-103.

Xie, X. Y., & Yu, C. (2019). Perceptual learning of Vernier discrimination transfers from high to zero noise after double training. Vision Research, 156, 39-45.

Zhang, J.-Y., & Yu, C. (2018). Vernier learning with short- and long-staircase training and its transfer to a new location with double training. Journal of Vision, 18(13):8, 1–8.

Xie, X. Y. & Yu, C. (2018). Double training downshifts the threshold vs. noise contrast (TvC) functions. Vision Research, 152, 3-9.

Kuai, S. G., Li, W., Yu, C., & Kourtzi, Z. (2017). Contour integration over time: Psychophysical and fMRI evidence, Cerebral Cortex, 27, 3042-3051

Han, Q.M., Cong, L.J., Yu, C., & Liu, L. (2017). Developing a logarithmic Chinese reading acuity chart. Optometry and Vision Science, 94(6):714-724.

Xiong, Y.Z., Zhang, J.Y., & Yu, C. (2016). Bottom-up and top-down influences at untrained conditions determine perceptual learning specificity and transfer. eLife, 5:e14614.

Yin, C., Bi, Y.Q., Yu, C., & Wei, K.L. (2016). Eliminating direction specificity in visuomotor learning. Journal of Neuroscience, 36(13):3839-3847.

Wang, R., Wang, J., Zhang, J.Y., Xie, X.Y., Yang, Y.X., Luo, S.H., Yu, C., & Li, W. (2016). Perceptual learning at a conceptual level. Journal of Neuroscience, 36(7):2238-2246.

Zhang, J.Y., & Yu, C. (2016). The transfer of motion direction learning to an opposite direction enabled by double training: A reply to Liang et al. (2015). Journal of Vision, 16(3):29, 1-4.

Cong, L.J., Wang, R.J., Yu, C. & Zhang, J.Y. (2016). Perceptual learning of basic visual features remains task specific with Training-Plus-Exposure (TPE) training. Journal of Vision, 16(3):13, 1-9.

Xiong, Y. Z., Xie, X. Y., & Yu, C. (2016). Location and direction specificity in motion direction learning associated with a single-level method of constant stimuli. Vision Research, 119, 9–15.

Zhang, G.L., Li, H., Song, Y., & Yu, C. (2015). ERP C1 is top-down modulated by orientation perceptual learning. Journal of Vision, 15(10):8, 1-11.

Xiong, Y.Z., Yu, C., & Zhang, J.Y. (2015). Perceptual learning eases crowding by reducing recognition errors but not position errors. Journal of Vision, 15(11):16, 1-13.

Wang, R., Zhang J.Y., Klein, S. A., Levi, D. M. & Yu, C. (2014). Vernier perceptual learning transfers to completely untrained retinal locations after double training: a piggybacking effect. Journal of Vision, 14(13):12, 1-10.

Zhang, J.Y., Cong, L.J., Klein, S. A., Levi, D. M. & Yu, C. (2014). Perceptual learning improves adult amblyopic vision through rule-based cognitive compensation. Investigative Ophthalmology & Visual Science, 55, 2020-2030.

Wang, R., Cong, L.J., & Yu, C. (2013). The classical TDT perceptual learning is mostly temporal learning. Journal of Vision, 13(5):9, 1-9.

Zhang, G.L., Cong, L.J., Song, Y., & Yu, C. (2013). ERP P1-N1 changes associated with Vernier perceptual learning and its location specificity and transfer. Journal of Vision, 13(4):19, 1-13.

Wang, R., Zhang, J.Y., Klein, S. A., Levi, D. M. & Yu, C. (2012). Task relevancy and demand modulate double-training enabled transfer of perceptual learning. Vision Research, 61, 33-38.

Zhang, J.Y., Zhang, G.L., Liu, L., & Yu, C. (2012). Whole report uncovers correctly identified but incorrectly placed target information under visual crowding. Journal of Vision, 12(7):5, 1-11.

Liu, X. Y., Zhang, T., Jia, Y. L., Wang, N. L., & Yu, C. (2011). The therapeutic impact of perceptual learning on juvenile amblyopia with or without previous patching treatment. Investigative Ophthalmology & Visual Science, 52, 1531–1538.

Zhang, J.Y., Zhang, G.L., Xiao, L.Q., Klein, S. A., Levi, D. M. & Yu, C. (2010). Rule-based learning explains visual perceptual learning and its specificity and transfer. Journal of Neuroscience, 30, 12323-12328.

Zhang, T., Xiao, L. Q., Klein, S. A., Levi, D. M. & Yu, C. (2010). Decoupling location specificity from perceptual learning of orientation discrimination. Vision Research, 50, 368-374.

Liu, L., Klein, S.A., Xue, F., Zhang, J.Y., & Yu, C. (2009). Using geometric moments to explain human letter recognition near the acuity limit. Journal of Vision, 9(1):26, 1-18.

Zhang, J.Y., Zhang, T., Xue, F., Liu, L., & Yu, C. (2009). Legibility of Chinese characters in peripheral vision and the top-down influences on crowding. Vision Research, 49, 44-53.

Xiao, L. Q., Zhang, J.Y., Wang, R., Klein, S. A., Levi, D. M. & Yu, C. (2008). Complete transfer of perceptual learning across retinal locations enabled by double training. Current Biology, 18, 1922-1926.

Zhang, J.Y., Kuai, S.G., Xiao, L. Q., Klein, S. A., Levi, D. M. & Yu, C. (2008). Stimulus coding rules for perceptual learning. PLoS Biology, 6, 1651-1660.

Zhang, J.Y., Zhang, T., Xue, F., Liu, L., & Yu, C. (2007). Legibility of Chinese characters and its implications for visual acuity measurement in Chinese reading population. Investigative Ophthalmology & Visual Science, 48, 2383-2390.

Levi, D.M., Yu, C. , Kuai, S.G., & Rislove, E. (2007). Global contour processing in amblyopia. Vision Research, 47, 512-524.

Kuai, S.G. & Yu, C. (2006). Constant contour integration in peripheral vision for stimuli with good Gestalt properties. Journal of Vision, 6, 1412-20.

Kuai, S.G., Zhang, J.Y., Klein, S. A., Levi, D. M. & Yu, C. (2005). The essential role of stimulus temporal patterning in enabling perceptual learning. Nature Neuroscience, 8, 1497-1499.

Yu, C., Klein, S.A., & Levi, D.M. (2004). Perceptual learning in contrast discrimination and the (minimal) role of context. Journal of Vision, 4,169-182.

Yu, C. , Klein, S.A., & Levi, D.M. (2003). Cross- and iso- oriented surrounds modulate the contrast response function: The effect of surround contrast. Journal of Vision, 3，527-540.

Yu, C. , Klein, S.A., & Levi, D.M. (2002). Facilitation of contrast detection by cross-oriented surround stimuli and its psychophysical mechanisms. Journal of Vision, 2, 243-255.

Yu, C. , Klein, S.A., & Levi, D.M. (2001). Surround modulation of perceived contrast and the role of brightness induction. Journal of Vision, 1, 18-31.

Yu, C. & Levi, D.M. (2000). Surround modulation in human vision unmasked by masking experiments. Nature Neuroscience, 3, 724-728.

Yu, C. & Levi, D.M. (1999). The time course of psychophysical end-stopping. Vision Research, 39, 2063-2073.

Yu, C. & Levi, D.M. (1998). Rectification nonlinearity in cortical end-stopped perceptive field. Vision Research, 38, 3517-3530.

Yu, C. & Levi, D.M. (1998). Spatial frequency and orientation tuning in psychophysical end-stopping. Visual Neuroscience, 15, 585-595.

Yu, C. & Levi, D.M. (1998). Naso-temporal asymmetry of spatial interactions in strabismic amblyopia. Optometry and Vision Science, 75, 424-432.

Yu, C. & Levi, D.M. (1997). Spatial facilitation predicted with end-stopped spatial filters. Vision Research, 37, 3117-3127.

Yu, C. & Levi, D.M. (1997). Cortical components of the Westheimer function. Vision Research, 37, 2535-2544.

Yu, C. & Levi, D.M. (1997). End-stopping and length-tuning in psychophysical spatial filters. Journal of the Optical Society of America A, 14 , 2346-2354.

Yu, C. & Levi, D.M. (1997). Cortical end-stopped perceptive fields: Evidence from dichoptic and amblyopic studies. Vision Research, 37, 2261-2270.

Yu, C. & Essock, E.A. (1996). Spatial scaling of end-stopped perceptive fields: Differences in neural bases of end-zones, flanks, and centers. Vision Research, 36, 3129-3139.

Yu, C. & Essock, E.A. (1996). Psychophysical end-stopping associated with line target. Vision Research, 36, 2883-2896.