美国麻省理工（MIT）的一项研究可能有助于治疗感觉障碍（sensory disorders）。通常情况下，人用两只眼睛看东西会比较清晰，而出现感觉障碍的人则在盖住一只眼看东西时会比较好。MIT的研究人员确定出了让人“双眼看世界”的基因。
与马和老鹰不同（它们的眼睛长在头的两侧，能够看当两侧不同的场景），人类的两只眼睛只看到同一个场景。来自MIT的Picower学习和记忆研究所的研究人员鉴定出了负责将两只眼看到的图像混合起来形成在大脑中形成有用图像的基因。
这项研究的结果刊登在9月4日的Public Library of Science(PLoS) Biology上。该研究揭示出一种新基因是双眼看东西所必须的。
双眼视物使我们能感知深度（即能感知立体的事物）并进行详细的视觉加工过程。这些由每个眼睛投影的图像被排列并在大脑的视丘脑和皮层中匹配。
MIT的研究人员发现，基因Ten_m3和Bcl6在大脑视觉和触觉通路的早期发育中起到关键作用。Ten_m3似乎对大脑感知来自每只眼睛的两个不同图像至关重要。
在敲除了Ten_m3基因的小鼠中，来自两只眼的反射在大脑中被错配。因为每只眼的反射抑制来自另一只眼的反射，因此即使是在眼睛能正常工作时，小鼠也是瞎的。
引人注意的是，研究人员发现当一只眼睛的输出信息在分子水平上被抑制时，敲除小鼠可能再获光明。当一只眼的冲突输入被关闭时，另外一只眼睛就能正常工作了，尽管只是单眼视觉。这个功能恢复的例子证实这种基因直接负责创造出来自两眼的相配的反射。
视觉的形成需要有完整的视觉分析器，包括眼球和大脑皮层枕叶，以及两者之间的视路系统。由于光线的特性，人眼对光线的刺激可以产生相当复杂的反应，表现有多种功能。当人们看东西时，物体的影像经过瞳孔和晶状体，落在视网膜上，视网膜上的视神经细胞在受到光刺激后，将光信号转变成生物电信号，通过神经系统传至大脑，再根据人的经验、记忆、分析、判断、识别等极为复杂的过程而构成视觉，在大脑中形成物体的形状、颜色等概念。
人的眼睛不仅可以区分物体的形状、明暗及颜色，而且在视觉分析器与运动分析器（眼肌活动等）的协调作用下，产生更多的视觉功能，同时各功能在时间上与空间上相互影响，互为补充，使视觉更精美、完善。因此视觉为多功能名称，我们常说的视力仅为其内容之一，广义的视功能应由视觉感觉、量子吸收、特定的空间时间构图及心理神经一致性四个连续阶段组成。
原始出处:
PLoS Biology
Ten_m3 Regulates Eye-Specific Patterning in the Mammalian Visual Pathway and Is Required for Binocular Vision
Catherine A. Leamey1,2*, Sam Merlin1, Paul Lattouf1, Atomu Sawatari1, Xiaohong Zhou3, Natasha Demel1, Kelly A. Glendining1, Toshitaka Oohashi3, Mriganka Sur2, Reinhard Fässler3
1 Department of Physiology, Bosch Institute and School of Medical Sciences, University of Sydney, Sydney, Australia, 2 Brain and Cognitive Sciences and Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America, 3 Department of Molecular Medicine, Max-Planck Institute for Biochemistry, Martinsried, Germany
Binocular vision requires an exquisite matching of projections from each eye to form a cohesive representation of the visual world. Eye-specific inputs are anatomically segregated, but in register in the visual thalamus, and overlap within the binocular region of primary visual cortex. Here, we show that the transmembrane protein Ten_m3 regulates the alignment of ipsilateral and contralateral projections. It is expressed in a gradient in the developing visual pathway, which is consistently highest in regions that represent dorsal visual field. Mice that lack Ten_m3 show profound abnormalities in mapping of ipsilateral, but not contralateral, projections, and exhibit pronounced deficits when performing visually mediated behavioural tasks. It is likely that the functional deficits arise from the interocular mismatch, because they are reversed by acute monocular inactivation. We conclude that Ten_m3 plays a key regulatory role in the development of aligned binocular maps, which are required for normal vision.
Received: February 2, 2007; Accepted: July 9, 2007; Published: September 4, 2007
* To whom correspondence should be addressed. E-mail: cathy@physiol.usyd.edu.au
Figure 1.Expression of Ten_m3 in Developing Visual Pathway
The expression of Ten_m3 is shown using in situ hybridisation (A) and (B) or immunohistochemistry (C).
(A) Coronal section through the retina at E16. Ten_m3 is highly expressed in the retinal ganglion cell layer where it is highest in ventral retina (arrow).
(B) Coronal section through the dLGN at P0. Ten_m3 is expressed high dorsally (arrow) and low ventrally.
(C) Coronal section through the dLGN showing immunoreactivity for Ten_m3. Expression is highest in the dorsal region of the nucleus (arrow). High expression is also seen laterally in the optic tract (OT) and in the vLGN. Expression is also visible in fine fascicles traversing the nucleus (small arrowhead) and in larger bundles that appear to be heading to and/or from the internal capsule (large arrowhead). The dashed line delineates the boundaries of the dLGN in (B) and (C). Orientations are as indicated. D, dorsal; L, lateral; M, medial. Scale bars indicate 100 μm.
(D–F) Graphs plotting relative Ten_m3 expression at P0–2. Ten_m3 mRNA is graded across the dorsoventral axis of the retina (D) and the DM-VL axis of the dLGN ([E] DM-VL axis illustrated by the double-headed arrow in [B]). Expression levels of Ten_m3 protein (F) are also graded along the DM-VL axis of the dLGN.
