Institute of Cognitive Neuroscience, University College London, London WC1N 3AR, United Kingdom, Wellcome Trust Centre for Neuroimaging, University College London, London WC1N 3BG, United Kingdom, and College of Mechatronic Engineering and Automation, National University of Defense Technology, Changsha, Hunan 410073, China.
J Neurosci. 2013 Nov 27;33(48):18781-91. doi: 10.1523/JNEUROSCI.4201-12.2013.
Visual perception depends strongly on spatial context. A classic example is the tilt illusion where the perceived orientation of a central stimulus differs from its physical orientation when surrounded by tilted spatial contexts. Here we show that such contextual modulation of orientation perception exhibits trait-like interindividual diversity that correlates with interindividual differences in effective connectivity within human primary visual cortex. We found that the degree to which spatial contexts induced illusory orientation perception, namely, the magnitude of the tilt illusion, varied across healthy human adults in a trait-like fashion independent of stimulus size or contrast. Parallel to contextual modulation of orientation perception, the presence of spatial contexts affected effective connectivity within human primary visual cortex between peripheral and foveal representations that responded to spatial context and central stimulus, respectively. Importantly, this effective connectivity from peripheral to foveal primary visual cortex correlated with interindividual differences in the magnitude of the tilt illusion. Moreover, this correlation with illusion perception was observed for effective connectivity under tilted contextual stimulation but not for that under iso-oriented contextual stimulation, suggesting that it reflected the impact of orientation-dependent intra-areal connections. Our findings revealed an interindividual correlation between intra-areal connectivity within primary visual cortex and contextual influence on orientation perception. This neurophysiological-perceptual link provides empirical evidence for theoretical proposals that intra-areal connections in early visual cortices are involved in contextual modulation of visual perception.
视觉感知强烈依赖于空间上下文。一个经典的例子是倾斜错觉，即当中央刺激物被倾斜的空间上下文包围时，其感知到的方向与其物理方向不同。在这里，我们表明，这种方向感知的上下文调制表现出个体间特有的多样性，与人类初级视觉皮层内个体间有效连通性的差异相关。我们发现，空间上下文引起错觉方向感知的程度，即倾斜错觉的幅度，在健康成年人中以个体特有的方式变化，与刺激大小或对比度无关。与方向感知的上下文调制平行，空间上下文的存在影响了分别对空间上下文和中央刺激作出反应的人类初级视觉皮层中周围和中央区域之间的有效连通性。重要的是，这种来自周围到中央初级视觉皮层的有效连通性与倾斜上下文刺激下的错觉感知个体差异相关，但与同方向上下文刺激下的有效连通性无关，这表明它反映了与方向相关的区域内连接的影响。我们的发现揭示了初级视觉皮层内区域间连通性与方向感知的上下文影响之间的个体间相关性。这种神经生理-知觉联系为理论假设提供了经验证据，即早期视觉皮层中的区域内连接参与了视觉感知的上下文调制。
