King A J, Jiang Z D, Moore D R
University Laboratory of Physiology, Oxford, United Kingdom.
J Comp Neurol. 1998 Jan 19;390(3):342-65.
The mammalian superior colliculus (SC) contains a neural map of auditory space. It is not known whether this topographic representation emerges at the level of the SC or is relayed there from other auditory areas. We have used retrograde labelling techniques in ferrets to examine the sources and pattern of innervation from auditory brainstem nuclei. After multiple injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) into the SC, the heaviest concentrations of labelled cells were found in the nucleus of the brachium (BIN) and external nucleus of the inferior colliculus, with much weaker labelling in the nucleus sagulum, dorsal, intermediate and ventral nuclei of the lateral lemniscus, paralemniscal regions, and periolivary nuclei. The projections were predominantly ipsilateral, although labelled cells were found on both sides of the brainstem. Single injections of WGA-HRP or discrete injections of red and green latex microspheres revealed that the caudal and lateral regions of the SC receive the heaviest projections, although the majority of the retrogradely labelled neurons in the contralateral BIN project to rostral SC. On the ipsilateral side, neurons in rostral and caudal regions of the BIN were labelled primarily by the tracer injected into rostral and caudal regions of the SC, respectively. However, no clear segregation was apparent in the BIN after injections into the medial and lateral regions or in any of the other nuclei after either injection paradigm. These data suggest that converging inputs from several auditory brainstem nuclei contribute to the construction of the auditory space map in the SC, although information about sound azimuth may be conveyed to this nucleus via a spatially ordered projection from the ipsilateral BIN.
哺乳动物的上丘（SC）包含听觉空间的神经图谱。目前尚不清楚这种拓扑表征是在上丘水平出现的，还是从其他听觉区域中继到上丘的。我们利用雪貂的逆行标记技术来研究听觉脑干核的神经支配来源和模式。将与辣根过氧化物酶结合的小麦胚芽凝集素（WGA-HRP）多次注射到上丘后，在臂旁核（BIN）和下丘外侧核中发现标记细胞的浓度最高，而在矢状核、外侧丘系背核、中间核和腹核、旁丘系区域以及橄榄周核中的标记则弱得多。这些投射主要是同侧的，尽管在脑干两侧都发现了标记细胞。单次注射WGA-HRP或分别注射红色和绿色乳胶微球表明，上丘的尾侧和外侧区域接受的投射最重，尽管对侧BIN中大多数逆行标记的神经元投射到上丘的嘴侧。在同侧，BIN嘴侧和尾侧区域的神经元分别主要由注入上丘嘴侧和尾侧区域的示踪剂标记。然而，在将示踪剂注入内侧和外侧区域后，BIN中没有明显的明显分离，在任何一种注射模式后，其他核中也没有明显分离。这些数据表明，来自几个听觉脑干核的汇聚输入有助于构建上丘中的听觉空间图谱，尽管关于声音方位的信息可能通过同侧BIN的空间有序投射传递到该核。
