Color responses of the human lateral geniculate nucleus: [corrected] selective amplification of S-cone signals between the lateral geniculate nucleno and primary visual cortex measured with high-field fMRI.
Color responses of the human lateral geniculate nucleus: [corrected] selective amplification of S-cone signals between the lateral geniculate nucleno and primary visual cortex measured with high-field fMRI.
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DOI：
10.1111/j.1460-9568.2008.06476.x
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发表时间：
2008-11
期刊：
影响因子：
--
通讯作者：
Hess RF
中科院分区：
文献类型：
--
作者：
Mullen KT;Dumoulin SO;Hess RF
外侧膝状核 (LGN) 是初级丘脑核，将视觉信息从视网膜传递到初级视觉皮层 (V1)，并已在非人类灵长类动物中得到广泛研究。 LGN 的一个关键特征是将视网膜输入分离到不同的细胞层，其特征是它们对红绿 (RG) 颜色（L/M 对手）、蓝黄 (BY) 颜色（S 锥体对手）和消色差 (Ach) 对比度的不同反应。在这项研究中，我们使用高场功能磁共振成像（4特斯拉，3.6 × 3.6 × 3 mm3）同时记录人类LGN和V1对色彩和乙酰胆碱对比度的反应，以研究LGN对颜色的反应，以及如何将这些反应修改为LGN和皮质之间的信息传递。我们发现 LGN 对 RG 颜色对比度具有鲁棒的响应，等于或大于 Ach 响应，但对 BY 对比度的敏感度明显较差。然而，在低时间速率 (2 Hz) 的 V1 中，BY 颜色通路的敏感性选择性增强，相对于 RG 和 Ach 响应上升。我们发现这种效应普遍存在于不同的刺激对比度和空间刺激（一维和二维模式）中，但对时间频率具有选择性，因为在 8 Hz 的刺激中没有发现这种效应。虽然 BY 色觉皮质增强的机制及其动态成分尚不清楚，但其作用可能是补偿源自视网膜和 LGN 神经元稀疏分布的微弱 BY 信号。
The lateral geniculate nucleus (LGN) is the primary thalamic nucleus that relays visual information from the retina to the primary visual cortex (V1) and has been extensively studied in non-human primates. A key feature of the LGN is the segregation of retinal inputs into different cellular layers characterized by their differential responses to red-green (RG) color (L/M opponent), blue-yellow (BY) color (S-cone opponent) and achromatic (Ach) contrast. In this study we use high-field functional magnetic resonance imaging (4 tesla, 3.6 × 3.6 × 3 mm3) to record simultaneously the responses of the human LGN and V1 to chromatic and Ach contrast to investigate the LGN responses to color, and how these are modified as information transfers between LGN and cortex. We find that the LGN has a robust response to RG color contrast, equal to or greater than the Ach response, but a significantly poorer sensitivity to BY contrast. In V1 at low temporal rates (2 Hz), however, the sensitivity of the BY color pathway is selectively enhanced, rising in relation to the RG and Ach responses. We find that this effect generalizes across different stimulus contrasts and spatial stimuli (1-d and 2-d patterns), but is selective for temporal frequency, as it is not found for stimuli at 8 Hz. While the mechanism of this cortical enhancement of BY color vision and its dynamic component is unknown, its role may be to compensate for a weak BY signal originating from the sparse distribution of neurons in the retina and LGN.
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