Most superficial sublamina of rat superior colliculus: Neuronal response properties and correlates with perceptual figure-ground segregation
Most superficial sublamina of rat superior colliculus: Neuronal response properties and correlates with perceptual figure-ground segregation
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DOI：
10.1152/jn.00059.2007
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发表时间：
2007-07-01
影响因子：
2.5
通讯作者：
Lund, R. D.
中科院分区：
文献类型：
--
作者：
Girman, S. V.;Lund, R. D.
上级丘（SC）的最上层（浅灰色层，SGS）提供了从视网膜到视纹外系统和视神经系统的重要通道。大多数的注意力已经给予了这个“视觉”SC在扫视生成和目标选择中的作用，并且它通常被认为在视觉感知中不太重要。然而，我们已经发现，在大鼠的SGS 1中，SGS最表层的部分，神经元对视觉信息进行非常复杂的分析。首先，在研究它们对各种闪光刺激的反应时，我们发现神经元对亮度变化本身没有反应，而是对它们感受野（RF）中视觉形状的出现和/或消失有反应。相反，在视觉处理的早期阶段的神经元的传统RF，在SGS 1的RF不能被描述的兴奋性和抑制性输入的固定空间分布。第二，SGS 1神经元表现出强大的方向调谐漂移光栅和定向特定调制的中心响应周围。这些是以前只在视觉皮层神经元中看到的特征，并被认为涉及“轮廓”感知和图形背景分离。第三，SGS 1神经元的反应表现出复杂的动力学，通常的反应调谐变得越来越尖锐的重复光栅周期。我们的结论是，SGS 1神经元参与了相当复杂的分析视网膜输入比以前认为的。SGS 1可能参与图形-背景分离的早期阶段，并在视觉去皮质后遇到的低分辨率无意识视觉中发挥作用。
The uppermost layer (stratum griseum superficiale, SGS) of the superior colliculus (SC) provides an important gateway from the retina to the visual extrastriate and visuomotor systems. The majority of attention has been given to the role of this "visual" SC in saccade generation and target selection and it is generally considered to be less important in visual perception. We have found, however, that in the rat SGS1, the most superficial division of the SGS, the neurons perform very sophisticated analysis of visual information. First, in studying their responses with a variety of flashing stimuli we found that the neurons respond not to brightness changes per se, but to the appearance and/or disappearance of visual shapes in their receptive fields (RFs). Contrary to conventional RFs of neurons at the early stages of visual processing, the RFs in SGS1 cannot be described in terms of fixed spatial distribution of excitatory and inhibitory inputs. Second, SGS1 neurons showed robust orientation tuning to drifting gratings and orientation-specific modulation of the center response from surround. These are features previously seen only in visual cortical neurons and are considered to be involved in "contour" perception and figure ground segregation. Third, responses of SGS1 neurons showed complex dynamics; typically the response tuning became progressively sharpened with repetitive grating periods. We conclude that SGS1 neurons are involved in considerably more complex analysis of retinal input than was previously thought. SGS1 may participate in early stages of figure-ground segregation and have a role in low-resolution nonconscious vision as encountered after visual decortication.