Jones Helen E, Andolina Ian M, Shipp Stewart D, Adams Daniel L, Cudeiro Javier, Salt Thomas E, Sillito Adam M
Department of Visual Neuroscience, University College London Institute of Ophthalmology, London EC1V 9EL, United Kingdom;
Beckman Vision Center, University of California, San Francisco, CA 94143; and.
Proc Natl Acad Sci U S A. 2015 Jun 2;112(22):7085-90. doi: 10.1073/pnas.1405162112. Epub 2015 Apr 21.
Figure-ground discrimination refers to the perception of an object, the figure, against a nondescript background. Neural mechanisms of figure-ground detection have been associated with feedback interactions between higher centers and primary visual cortex and have been held to index the effect of global analysis on local feature encoding. Here, in recordings from visual thalamus of alert primates, we demonstrate a robust enhancement of neuronal firing when the figure, as opposed to the ground, component of a motion-defined figure-ground stimulus is located over the receptive field. In this paradigm, visual stimulation of the receptive field and its near environs is identical across both conditions, suggesting the response enhancement reflects higher integrative mechanisms. It thus appears that cortical activity generating the higher-order percept of the figure is simultaneously reentered into the lowest level that is anatomically possible (the thalamus), so that the signature of the evolving representation of the figure is imprinted on the input driving it in an iterative process.
图形-背景辨别是指对一个物体（即图形）相对于无明显特征背景的感知。图形-背景检测的神经机制与高级中枢和初级视觉皮层之间的反馈相互作用有关，并被认为是全局分析对局部特征编码影响的指标。在此，在对警觉灵长类动物视觉丘脑的记录中，我们证明，当由运动定义的图形-背景刺激的图形成分（而非背景成分）位于感受野上时，神经元放电会有显著增强。在这种范式中，两种条件下感受野及其附近区域的视觉刺激是相同的，这表明反应增强反映了更高层次的整合机制。因此，似乎产生图形的高阶感知的皮层活动同时逆向传入到解剖学上可能的最低层次（丘脑），从而使图形不断演变的表征特征在一个迭代过程中被印刻在驱动它的输入上。
