STUDY ON THE RECONSTRUCTION OF VISUAL PATHWAYS

1.猫视神经再生的研究1)作为前人研究的延续，我们从视网膜神经节细胞轴突再生的坐骨神经纤维中记录了260个视觉反应单位。我们确认了Y细胞的数量多于X细胞和其他细胞，并进一步发现，在X细胞中没有偏心细胞，而在Y细胞中，ON和OFF都被采样。2)生物细胞素行顺行标记后，观察再生视神经轴突的横截面，发现猫再生视神经轴突大部分为无髓轴突，有髓纤维之间的直径范围比正常猫的视神经轴突的直径范围小。3)对视神经切断后存活2个月的神经节细胞，采用逆行标记结合荧光黄细胞内注射的方法，研究神经节细胞的形态。与其他类型的细胞相比，Alpha(Y)细胞对轴突切断的抵抗力最强。V-…的功能恢复在成年仓鼠身上进行了更多的视觉研究，这些成年仓鼠通过周围神经移植重建了视网膜小球投射。在使用光刺激作为条件刺激的条件性回避行为过程中，四只仓鼠中有两只获得了回避分数的相对视力恢复。对于这两种动物，我们成功地通过WGA-HRP顺行标记将再生的视网膜轴突追踪到上丘。此外，我们还成功地获得了光刺激眼睛后的脑电去同步化，并通过周围神经移植桥接到丘脑。在视神经切断后2~30d观察神经营养因子BDNF、NT3、NT4对视网膜神经节细胞轴突再生的影响。细胞内注射神经生物素显示了再生轴突的详细形态，如在整个支架制备中反复出现的轴突和侧枝。BDNF被发现最有效地增加了偶尔有侧枝的复发轴突的数量。较少

1. Studies on optic nerve regeneration in cats1) As a continuation of the previous study we recorded 260 visually responsive units from teased fibers of the sciatic nerve through which retinal ganglions cell axon regenerated. We confirmed the outnumber of Y cells than X and other cells and further found that among X cells there was no OFF center cell while in Y cells both ON and OFF were sampled. 2) After anterograde labeling with biocytin we studied the cross section of the regenerated optic axons and found that most of the axons were unmyelinated and the diameter range was smaller even among myelinated fibers as compared with the diameter range of normal optic axons in cats. 3) Morphological types of ganglions cells which survived for 2 months after optic nerve section were studied by a retrograde labeling method coupled with intracellular injections of Lucifer Yellow. alpha (Y)cells turned out to be the most resistant to axotomy over the other cells types.2. Functional recovery of v … More ision was studied in adult hamsters with a reconstructed retinocolliclar projection by the peripheral nerve transplant. In two hamsters out of four relative recovery of vision was obtained in avoidance score during the session of conditioned avoidance behavior using a light stimuli as a conditioning stimulus. For these two animals we succeed to trace regenerated retinal axons into the superior colliculus by an anterograde labeling with WGA-HRP. Furthermore we succeeded to obtain EEG desynchronization after photic stimulation into the eye which was bridged to the colliculus with a peripheral nerve graft.3. Effects of neurotrophic factors such BDNF, NT3, NT4 on axonal regeneration of retinal ganglion cells were studied 2-30 days after optic nerve section. Intracellular injections of neurobiotin revealed detailed morphology of regenerating axons such as recurring axons and side branches within the whole mount preparation. BDNF was found most effective to increase the number of recurring axons with occasional side branches. Less