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首页> 外文期刊>Journal of vision >S-Cone Induced Cortical activity Despite an ON-Pathway Defect; a BOLD fMRI-Based Case Study
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S-Cone Induced Cortical activity Despite an ON-Pathway Defect; a BOLD fMRI-Based Case Study

机译：尽管存在通路缺陷，但S锥诱导的皮层活动;基于大胆功能磁共振成像的案例研究

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Rods and S-cones synapse with ON-bipolar cells that use the same metabotropic glutamate receptor, mGluR6. Strikingly, in individuals where mGluR6 signaling is interrupted by GRM6 mutations, rod vision is lost, but normal color vision is retained despite the absence of S-ON bipolar input. Here we report the first neuroimaging study of a GRM6-/- patient. BOLD fMRI was used to measure cortical activity in visual areas V1a??V3, V4, VO, V3a, and MT in response to diffuse stimuli presented monocularly, that were chromatically modulated to stimulate specifically either S or M+L cones at frequencies of 1a??20 Hz. Robust cortical activity was elicited in both conditions and the overall pattern was similar to control subjects. This suggests that the H2 horizontal cell to OFF-bipolar pathwaya??not S-cone to ON- bipolar and small-bistratified cellsa??are responsible for normal blue- yellow hue perception. Moreover, we propose that inner retina crossover inhibition between ON- and OFF-pathways explains the remarkably normal photopic vision in GRM6 patients. Some quantitative differences were evident, most notable was attenuation of both S and M+L signals at high temporal frequencies (7 Hz) suggesting that the higher level, ON-OFF pathway interactions shape the temporal properties of both S and M/L pathways in normal observers.
机译：杆和S-锥与使用相同的代谢型谷氨酸受体mGluR6的双极型ON突触。令人惊讶的是，在mGluR6信号被GRM6突变打断的个体中，视杆视力丧失，但尽管没有S-ON双极输入，仍能保持正常的色觉。在这里，我们报告了对GRM6-/-患者的首次神经影像学研究。大胆功能磁共振成像用于测量视觉区域V1a ?? V3，V4，VO，V3a和MT的皮层活动，以响应单眼呈现的弥漫性刺激，对它们进行色调制以专门刺激频率为1a的S或M + L视锥细胞20 Hz。在这两种情况下都引发了强大的皮层活动，并且总体模式与对照组相似。这表明H2水平细胞到OFF-双极途径，而不是S-锥体到ON-双极和小受精化细胞，负责正常的蓝黄色调。此外，我们建议在ON和OFF通路之间的内部视网膜交叉抑制可以解释GRM6患者的显着正常视力视觉。数量上的差异是显而易见的，最显着的是在高时间频率（> 7 Hz）下S和M + L信号的衰减，表明较高水平的ON-OFF途径相互作用决定了S和M / L途径的时间特性。在正常观察者中。

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