Melanopsin Contributions to the Representation of Images in the Early Visual System.
Melanopsin Contributions to the Representation of Images in the Early Visual System.
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DOI：
10.1016/j.cub.2017.04.046
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发表时间：
2017-06-05
期刊：
影响因子：
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通讯作者：
Lucas RJ
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文献类型：
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作者：
Allen AE;Storchi R;Martial FP;Bedford RA;Lucas RJ
黑视素光接受增强视网膜对环境光（辐照度）变化的反应，并驱动非图像形成的视觉反射，如昼夜节律干扰。黑视素的信号也会到达大脑中负责形成视觉的区域，但黑视素对视觉图像编码的贡献（如果有的话）仍不清楚。我们使用受体沉默替代的原理来解决这一缺陷，在图像中，黑视素与杆+锥的可见性是独立调节的，我们记录了小鼠背外侧膝状核（dLGN；丘脑皮层视觉中继）的诱发反应。大约20%的dLGN单位对只有黑视素可见的模式有反应，这表明黑视素信号单独可以传递空间信息。使用黑视素隔离刺激绘制的空间感受野（RFs）具有直径约13°的ON中心。黑视素和杆状+锥反应在颞域不同，当刺激对黑视素不可见时，对缓慢变化的亮度（<0.9 Hz）和静止图像的反应不足。我们利用这些数据设计并测试了黑视素参与形式视觉的数学模型，并将其与进一步的实验记录一起应用于在模拟自然场景的主动视图下探索黑视素信号。我们的研究结果表明，黑视素增强了丘脑对包含局部辐射相关性的场景的表征，补偿了视锥视觉的高时间频率偏差以及视场方向变化的幅度和频率之间的负相关。总之，这些数据揭示了黑视素对编码视觉图像的独特贡献，预测在自然视图下，黑视素增强了早期视觉系统在中等空间尺度上编码模式的能力。黑视素扩展了小鼠早期视觉系统的时空范围，当黑视素不参与时，空间模式的表征就会缺失。我们定义了一个预测黑视素对模式视觉贡献的线性模型。Allen等人探讨了形式视觉的起源，并表明视网膜内感光体黑视素扩展了其时空范围。黑视素增加了空间尺度大于正在进行的视角变化的模式的表示。
Melanopsin photoreception enhances retinal responses to variations in ambient light (irradiance) and drives non-image-forming visual reflexes such as circadian entrainment. Melanopsin signals also reach brain regions responsible for form vision, but melanopsin’s contribution, if any, to encoding visual images remains unclear. We addressed this deficit using principles of receptor silent substitution to present images in which visibility for melanopsin versus rods+cones was independently modulated, and we recorded evoked responses in the mouse dorsal lateral geniculate nucleus (dLGN; thalamic relay for cortical vision). Approximately 20% of dLGN units responded to patterns visible only to melanopsin, revealing that melanopsin signals alone can convey spatial information. Spatial receptive fields (RFs) mapped using melanopsin-isolating stimuli had ON centers with diameters ∼13°. Melanopsin and rod+cone responses differed in the temporal domain, and responses to slow changes in radiance (<0.9 Hz) and stationary images were deficient when stimuli were rendered invisible for melanopsin. We employed these data to devise and test a mathematical model of melanopsin’s involvement in form vision and applied it, along with further experimental recordings, to explore melanopsin signals under simulated active view of natural scenes. Our findings reveal that melanopsin enhances the thalamic representation of scenes containing local correlations in radiance, compensating for the high temporal frequency bias of cone vision and the negative correlation between magnitude and frequency for changes in direction of view. Together, these data reveal a distinct melanopsin contribution to encoding visual images, predicting that, under natural view, melanopsin augments the early visual system’s ability to encode patterns over moderate spatial scales. A five-primary display is used to define melanopsin’s contribution to form vision Melanopsin extends the spatiotemporal range of the mouse early visual system The representation of spatial patterns is deficient when melanopsin is not engaged A linear model predicting melanopsin’s contribution to pattern vision is defined Allen et al. probe the origins of form vision and show that the inner retinal photoreceptor, melanopsin, extends its spatiotemporal range. Melanopsin augments the representation of patterns whose spatial scale is larger than that of ongoing changes in direction of view.