Deng C, Rogers L J
Division of Neuroscience and Animal Behaviour, School of Biological Sciences, University of New England, Armidale, NSW, Australia.
J Comp Neurol. 1998 May 4;394(2):171-85.
The organisation of the neural projections from the optic tectum and pretectal nuclei complex, n. subpretectalis / n. interstitio-pretecto-subpretectalis (SP/IPS), to the nucleus rotundus (Rt) in chicks was studied by using retrograde tracing techniques. After the injection of fluorescent retrograde tracers, rhodamine-conjugated latex microspheres, fluorescein-conjugated latex microspheres, True Blue, Fluoro-Gold, or rhodamine B isothiocyanate, into different regions of Rt and its middorsal extension, the nucleus triangularis (T), the distribution of retrogradely labelled neuronal cell bodies in the tectum and pretectal nuclei was assessed. Both the ipsilateral and contralateral tectorotundal projections were found to be organised topographically in as much as different sublaminas of the stratum griseum centrale (SGC) project in an orderly manner to Rt and T. The deepest stratum of SGC overlapping into the stratum album centrale projects to T. Deep SGC projects to the dorsal Rt and superficial SGC to the ventral Rt. A band running through the centre of Rt receives input from the central sublamina of SGC, and the caudal central Rt receives input from a deeper sublamina than does the rostral central Rt. The SP/IPS projects to the ipsilateral Rt only and the projection order is dorsal SP to dorsal Rt, ventral SP to ventral Rt and middle SP to the central band of Rt. The neurones in IPS and the nucleus of the tractus tectothalamicus project to T. Thus, Rt and T receive topographically both tecto- (excitatory) and SP/IPS- (inhibitory) projections. The possible functional implications for parallel information processing in these projections are discussed.
运用逆行追踪技术，研究了雏鸡中从视顶盖和顶盖前核复合体（即顶盖前下核/顶盖间-顶盖前-顶盖前下核，SP/IPS）到圆核（Rt）的神经投射组织。将荧光逆行示踪剂，如罗丹明偶联乳胶微球、荧光素偶联乳胶微球、真蓝、氟金或异硫氰酸罗丹明B，注入Rt及其背中部延伸区域——三角核（T）的不同部位后，评估顶盖和顶盖前核中逆行标记神经元胞体的分布。结果发现，同侧和对侧的顶盖-圆核投射均按拓扑结构组织，因为中央灰质层（SGC）的不同亚层会有序地投射到Rt和T。SGC最深层与中央白质层重叠部分投射到T。SGC深层投射到Rt背侧，浅层投射到Rt腹侧。一条贯穿Rt中心的带区接收来自SGC中央亚层的输入，而Rt中央尾侧部分比头侧部分接收来自更深亚层的输入。SP/IPS仅投射到同侧Rt，投射顺序为背侧SP投射到背侧Rt，腹侧SP投射到腹侧Rt，中间SP投射到Rt的中央带区。IPS和顶盖-丘脑束核中的神经元投射到T。因此，Rt和T在拓扑结构上均接收顶盖（兴奋性）和SP/IPS（抑制性）投射。文中讨论了这些投射中并行信息处理可能的功能意义。
