Mana S, Chevalier G
Université Pierre et Marie Curie, Département de Neurochimie-Anatomie, Institut des Neurosciences, 9 quai Saint Bernard, 75230 Paris Cedex 05, France.
Neuroscience. 2001;103(3):673-93. doi: 10.1016/s0306-4522(01)00026-4.
There is increasing evidence that acetylcholinesterase is organised in a lattice-like fashion in the intermediate layers of the mammalian superior colliculus. In a recent study, we described this organisation in rat by showing that it comprises a well formed honeycomb-like lattice with about 100 cylindrical compartments or modules occupying both the intermediate collicular layers. Considering this enzyme domain as a reference marker for comparing the organisation of collicular input-output systems, the present study investigates whether the principal sensori-motor systems in intermediate layers also have honeycomb-like arrangements. In 33 animals, the distributions of afferents (visual from extrastriate cortex; somatic from the primary somatosensory cortex, the trigeminal nucleus and the cervical spinal cord) and efferents (cells of origin of the crossed descending bulbospinal tract and uncrossed pathway to the pontine gray, the ascending system to the medial dorsal thalamus) were examined in a tangential plane following applications of horseradish peroxidase-wheatgerm agglutinin conjugate (used as an anterograde and retrograde tracer). In 22 of the 33 rats, axonal tracing was made within single tangential sections also stained for cholinesterasic activity in order to compare the neuron profiles with the cholinesterasic lattice.The results show that these afferent and efferent systems are also organised in honeycomb-like networks. Moreover, those related to the cortical, trigeminal and some of the spinal afferents are aligned with the cholinesterasic lattice. Likewise most of colliculo-pontine, colliculo-bulbospinal and half of colliculo-diencephalic projecting cells also tend to be in spatial register with the enzyme lattice. This indicates that the honeycomb-like arrangement is a basic architectural plan in the superior colliculus for the organisation of both acetylcholinesterase and major sensori-motor systems for orientation.
越来越多的证据表明，乙酰胆碱酯酶在哺乳动物上丘的中间层以晶格状方式组织。在最近的一项研究中，我们通过显示大鼠中的这种组织由一个结构良好的蜂窝状晶格组成，该晶格有大约100个圆柱形隔室或模块占据了上丘中间层，从而描述了这种组织。将这个酶域作为比较上丘输入-输出系统组织的参考标记，本研究调查中间层的主要感觉运动系统是否也有蜂窝状排列。在33只动物中，在应用辣根过氧化物酶-小麦胚凝集素共轭物（用作顺行和逆行示踪剂）后，在切向平面上检查传入神经（来自纹外皮层的视觉神经；来自初级躯体感觉皮层、三叉神经核和颈脊髓的躯体神经）和传出神经（交叉的下行延髓脊髓束的起源细胞和到脑桥灰质的不交叉通路、到内侧背侧丘脑的上行系统）的分布。在33只大鼠中的22只中，在也用胆碱酯酶活性染色的单个切向切片内进行轴突追踪，以便将神经元轮廓与胆碱酯酶晶格进行比较。结果表明，这些传入和传出系统也以蜂窝状网络组织。此外，那些与皮质、三叉神经和一些脊髓传入神经相关的系统与胆碱酯酶晶格对齐。同样，大多数上丘-脑桥、上丘-延髓脊髓和一半的上丘-间脑投射细胞也倾向于与酶晶格在空间上对齐。这表明蜂窝状排列是上丘中乙酰胆碱酯酶和主要感觉运动系统组织的基本结构模式，用于定向。
