Rods progressively escape saturation to drive visual responses in daylight conditions.
Rods progressively escape saturation to drive visual responses in daylight conditions.
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DOI：
10.1038/s41467-017-01816-6
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发表时间：
2017-11-27
影响因子：
16.6
通讯作者：
Münch TA
中科院分区：
文献类型：
--
作者：
Tikidji-Hamburyan A;Reinhard K;Storchi R;Dietter J;Seitter H;Davis KE;Idrees S;Mutter M;Walmsley L;Bedford RA;Ueffing M;Ala-Laurila P;Brown TM;Lucas RJ;Münch TA
视杆和视锥光感受器在较大的光强范围内支持视觉。视杆在昏暗光照下活跃，被认为在较高（明视）辐照度下会达到饱和。视杆饱和的程度尚未明确界定；一些研究报告称视杆活动在明视范围内仍很明显。通过对缺乏视锥以及视觉正常的小鼠的视网膜和背外侧膝状体核进行电生理记录，我们描述了影响明视条件下视杆驱动反应的刺激和生理因素。我们发现，在高辐照度下，视杆对比敏感度最初会大幅降低，但会逐渐恢复，从而能够对中等对比度的刺激产生反应。令人惊讶的是，在较高光照水平下视杆恢复得更快。一个视杆光转导模型表明，光转导增益调节和漂白适应是视杆恢复的基础。一致地，外源性生色团会降低在明亮背景下视杆的反应。因此，漂白适应使得小鼠视杆在任何辐照度下都能对适度的对比度产生反应。矛盾的是，在明视范围内提高辐照度会增强视杆反应的稳健性。
视杆光感受器被认为在强光下会达到饱和。在此，作者描述了介导小鼠视网膜中视杆光感受器反应饱和的生理参数，并表明视杆在明视条件下能够驱动视觉反应。
Rod and cone photoreceptors support vision across large light intensity ranges. Rods, active under dim illumination, are thought to saturate at higher (photopic) irradiances. The extent of rod saturation is not well defined; some studies report rod activity well into the photopic range. Using electrophysiological recordings from retina and dorsal lateral geniculate nucleus of cone-deficient and visually intact mice, we describe stimulus and physiological factors that influence photopic rod-driven responses. We find that rod contrast sensitivity is initially strongly reduced at high irradiances, but progressively recovers to allow responses to moderate contrast stimuli. Surprisingly, rods recover faster at higher light levels. A model of rod phototransduction suggests that phototransduction gain adjustments and bleaching adaptation underlie rod recovery. Consistently, exogenous chromophore reduces rod responses at bright background. Thus, bleaching adaptation renders mouse rods responsive to modest contrast at any irradiance. Paradoxically, raising irradiance across the photopic range increases the robustness of rod responses. Rod photoreceptors are thought to be saturated under bright light. Here, the authors describe the physiological parameters that mediate response saturation of rod photoreceptors in mouse retina, and show that rods can drive visual responses in photopic conditions.
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影响因子：
25
作者：
Altimus, Cara M.;Gueler, Ali D.;Alam, Nazia M.;Arman, A. Cyrus;Prusky, Glen T.;Sampath, Alapakkam P.;Hattar, Samer
通讯作者：
Hattar, Samer
影响因子：
--
作者：
Invergo, Brandon M.;Dell'Orco, Daniele;Bertranpetit, Jaume
通讯作者：
Bertranpetit, Jaume
影响因子：
56.9
作者：
GREEN, DG
通讯作者：
GREEN, DG
DOI：
10.1073/pnas.96.13.7553
发表时间：
1999-06-22
影响因子：
11.1
作者：
Biel, M;Seeliger, M;Hofmann, F
通讯作者：
Hofmann, F
影响因子：
5.5
作者：
CORNWALL, MC;FAIN, GL
通讯作者：
FAIN, GL