Demas Jay, Sagdullaev Botir T, Green Erick, Jaubert-Miazza Lisa, McCall Maureen A, Gregg Ronald G, Wong Rachel O L, Guido William
Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Neuron. 2006 Apr 20;50(2):247-59. doi: 10.1016/j.neuron.2006.03.033.
Axon terminals from the two eyes initially overlap in the dorsal-lateral geniculate nucleus (dLGN) but subsequently refine to occupy nonoverlapping territories. Retinal activity is required to establish and maintain this segregation. We show that despite the presence of retinal activity, segregated projections desegregate when the structure of activity is altered. Early in development, spontaneous retinal activity in the no b-wave (nob) mouse is indistinguishable from that of wild-type mice, and eye-specific segregation proceeds normally. But, around eye-opening, spontaneous and visually evoked activity in nob retinas become abnormal, coincident with a failure to preserve precise eye-specific territories. Dark-rearing studies suggest that altered visual experience is not responsible. Transgenic rescue of the mutated protein (nyctalopin) within nob retinal interneurons, without rescuing expression in either retinal projection neurons or their postsynaptic targets in the dLGN, restores spontaneous retinal activity patterns and prevents desegregation. Thus, normally structured spontaneous retinal activity stabilizes newly refined retinogeniculate circuitry.
来自两只眼睛的轴突终末最初在背外侧膝状核（dLGN）中重叠，但随后会细化以占据不重叠的区域。视网膜活动是建立和维持这种分离所必需的。我们发现，尽管存在视网膜活动，但当活动结构改变时，分离的投射会重新混合。在发育早期，无b波（nob）小鼠的视网膜自发活动与野生型小鼠无法区分，并且眼特异性分离正常进行。但是，在睁眼前后，nob视网膜中的自发和视觉诱发活动变得异常，同时无法保留精确的眼特异性区域。暗饲养研究表明，视觉经验改变并非原因所在。在nob视网膜中间神经元内对突变蛋白（夜盲蛋白）进行转基因拯救，而不在视网膜投射神经元或其在dLGN中的突触后靶点中拯救表达，可恢复视网膜自发活动模式并防止重新混合。因此，正常结构的视网膜自发活动稳定了新细化的视网膜膝状体回路。
