摘要
目的 :应用神经轴突示踪方法 ,研究人类视觉神经通路在胚胎期 12w时的发育情况。方法 :取 12w胎龄的胚胎 ,浸泡在 4 %的甲醛缓冲液中固定后 ,分别在视束、上丘臂和视皮质下植入DiI染料 (DiI,1,1’ dioctadecyl 3,3,3’ ,3’ tetramethylin docarbocyanineperchlorate)。于室温下放置 4w ,待DiI晶体充分扩散后 ,根据神经轴突方向切片 ,通过共焦激光扫描显微镜观察并记录结果。结果 :大体标本观察可见到 ,视网膜神经纤维投射已到达外侧膝状体、上丘。切片观察发现 :外侧膝状体处尚未出现分层现象 ;上丘处 ,来自视网膜的神经纤维位于上丘臂的背侧 ;视皮质下已存在板层结构 ,板层内神经元呈多种形态。结论 :通过神经轴突示踪技术发现 ,12w时视网膜的神经纤维投射已经到达外侧膝状体和上丘 ,视皮质下存在板层结构。这说明人类视觉神经通路发育存在“等待期”。
Objective: To reveal morphological features of visual system during early prenatal developm ent.Methods: A fetal brain(age 12 GW) was immersed in 4% formaldehyde for fixation. DiI(1,1'-dioctadecyl-3,3,3',3'-tetramethylin-docarbocyanine perchlorate) wa s em bedded into the optic tract,brachium of superior colliculus and in the intermed iate zone of the medial occipital lobe. The embedded brain tissue was incubated at room temperature for 4 weeks. And then the tissue was sectioned,mounted afte r DiI diffused through the entire axons of the visual system. The slides were ob served under confocal laser scanning microscopy.Results: It was showed that axons from retina have already reached lateral geniculate nuc leus(LGN) and superior colliculus(SC) in the brain tissue. Under the confocal laser scanning microscopy,retinogeniculate axon has already reached L GN but there is no cellular lamination. Axons from retina also have arrived at S C,and the fibers were distributed along the dorsal part of SC. There were subpl ates under visual cortex,and neurons within the subplate appeared to be polymor phous. Conclusion: The retinogeniculate axon reaches LGN by 12 ws,but cellular lamination does not. The axon from retina reaches SC and the subplate under visual cortex forms duri ng early prenatal fetus.
出处
《眼视光学杂志》
2004年第2期92-95,共4页
Chinese Journal of Optometry & Ophthalmology
基金
国家自然科学基金 (3 0 14 0 0 16
3 0 2 70 45 5 )
浙江省自然科学基金 (3 0 10 3 7)
教育部科学技术研究重点项目 (0 10 46)
浙江省医药卫生科学研究基金 (2 0 0 2B0 3 6)
