RETINA OF RIVER DOLPHIN LIPOTES VEXILLIFER

The structure of retina of the Lipotes Vexillifer has been studied quantitatively under light microscope. The results obtained are as follows.(ⅰ) The thickness of the retina is 268 μm. The lamination of retina can be clearly distinguished. It consists of 10 layers. The thicknesses of the layers from pigment epithelium to internal limiting membrane are 12 μm, 44 μm, 2 μm, 48 μm, 20 μm, 36 μm, 68 μm, 32 μm, 8 μm and 2 μm respectively.(ⅱ) The number of cells in the outer nuclear layer is larger than that in the inner nuclear layer. Two types of cell can be distinguished in this layer. The number of receptors and ganglion cells is in a ratio of 12 to 1. These results show that the retina type of the Lipotes corresponds to that of nocturnal animals.(ⅲ) The diameters of ganglion cells range 1.5—37 μm with two peaks at 6 μm and 35 μm. This means that the ganglion cells fall into two groups according to size, and this has been proved by the observation on morphology of ganglion cells in the wh     

中国南沙群岛卡拉凹顶藻化学成分研究

中国南沙群岛卡拉凹顶藻化学成分研究钟永利，苏镜娱，曾陇梅，阎素君，罗秉浩（中山大学化学系，广州，５１０２７５）关键词红藻，卡拉凹顶藻，木糖甙，β－十六烷基－Ｄ－吡喃木糖甙，胆甾醇凹顶藻（Ｌａｕｒｅｎｃｉａ）含有非常丰富的次生代谢产物，主要包括萜类和含...     

BINOCULAR RESPONSES IN THE SUPERIOR COLLICULUS OF THE ALBINO RAT

The retinotopic map for the contralateral eye is similar to that found in the pigmentedrats and in other rodents. Cells which had ipsilateral responses were recorded in a fairlylarge area in tale rostral portion of the tectum. Their receptive fields lay from about 40°in the contralateral hemifield to about 40°in the ipsilateral hemifield. The ipsilateral re-sponse of a binocular cell is similar in almost every respect to its counterpart in the oppositeeye except being very weak and that the receptive field is usually smaller. Most binocularcells are distributed in the Stratmn grisemn superfieiale (SGS) and the Stratum optieum (SO).Less binocular cells recorded in the Stratum griseum intermediale (SGI) have moro scatter-ed distribution both in the size and in the position of the receptive field.     

白鱀豚视觉通道的组织学研究——视网膜

本文对白(既鱼)豚视网膜进行了某些定量研究,并观察了其结构.1)视网膜厚度为268μ.2)外核层细胞数约为内核层细胞数的两倍,光感受器与神经本细胞数之比为12:1,这表明白(既鱼)豚视网膜属于夜间动物视网膜类型.3)神经节细胞直径范围为1.5—37μ,在6微米和35微米处有两个高峰.说明按胞体大小神经节细胞可分成两类.在视网膜不同部位,大小神经节细胞的比例变化不大.4)在视网膜上未见中央凹,也未见神经节细胞密度很高的中央区和视条纹。     

白鱀豚视觉通道的组织学研究——视神经结构、纤维计数和纤维直径谱

本文用电子显微镜和光学显微镜对采自长江的两头白鱀豚(Lipotes VexilliferMiller)的视神经(共4根)进行了组织结构和数量的研究. 4根视神经的纤维平均数为78,900根.纤维直径范围为0.35—7.45微米.峰直径为1.5微米.4根视神经的纤维直径谱都是单峰的.经统计分析,视神经中央区和周围区神经纤维的密度及直径大小都没有显著的差异.纤维的轴突直径(d)和整个纤维直径(D)之比d/D=0.60±0.02(P<0.05).在4根视神经中均末见到无髓鞘纤维.神经纤维横切面的形状很不规则.髓鞘的厚度很不一致,有些纤维的髓鞘极厚,有些纤维的髓鞘很薄.     

大白鼠上丘细胞的双眼反应

本文证明大白鼠对侧眼在上丘的投影图和有色素鼠或其它啮齿动物的相似.在上丘咀部很大的区域上都可以记录到有同侧反应的细胞,其感受野分布在从对侧40°到同侧40°的上视野内.除了感受野较小和反应极弱以外,双眼细胞的同侧反应与对侧反应在各方面都相似.大多数双眼细胞位于表面灰层(SGS)及视觉层(SO)内,在中间灰层(SGI)记录到的少数双眼细胞的感受野大小和位置分布比浅层的分散。     

大白鼠视皮层的胼胝体投射和视野垂直中线的关系

本文通过电生理学与HRP标记技术配合研究表明,大白鼠初级视皮层外侧边界与17/18a区边界一致,宽约1.5mm的胼胝体投射带沿此边界分布,边界位于带内,离其外侧界约1/3带宽。视野的垂直中线在皮层上有两处投影,一条在17区内,离胼胝体带内界约1/3带宽,另一条位于胼胝体带外界附近。     

STUDIES ON OPTIC NERVE OF LIPOTES VEXILLIFER——STRUCTURE, FIBER COUNT AND DIAMETER SPECTRUM

Four optic nerves obtained from two Lipotes Vexillifer have been studied with the aidof electron microscope. The fiber diameter spectra of all the four optic nerves are unimodal.The diameters of fibers range from 0.35 to 7.45 μm with the highest frequency at 1.5 μm. Ttest indicates there is no significant difference in fiber density and fiber diameter betweenthe central and peripheral regions of the optic nerve. The ratio of axon diameter to thetotal fiber diameter is 0.6 ± 0.02 (p<0.05). The examination of four optic nerves indicatesa mean count of 78,900 fibers; none of unmyelinated fibers have beer seen. The shapesof the cross sections of fibers are very irregular. The myelin sheaths of some nerve fibers arevery thick while those of some others are thinner.