Tellegen A J, Dubbeldam J L
Neurobehavioral Morphology, Institute of Evolutionary and Ecological Sciences, Leiden University, The Netherlands.
J Comp Neurol. 1999 Mar 15;405(3):281-98. doi: 10.1002/(sici)1096-9861(19990315)405:3<281::aid-cne1>3.0.co;2-y.
The supraspinal nucleus (SSp) in the mallard, which lies in the rostral spinal cord and caudal brainstem, is a motor nucleus that forms the rostral continuation of the ventral horn. It contains part of the motoneurons innervating the craniocervical muscles. Injections with horseradish peroxidase (HRP) and wheat germ agglutinin conjugated to HRP (WGA) in the SSp were used to localize the craniocervical premotor neurons in the medullary reticular formation. A mixture of WGA and HRP (WGA/HRP) or biotinylated dextran amine (BDA) were injected in the different reticular areas to test the results. Small numbers of craniocervical premotor neurons were found bilaterally in the ventromedial part of the parvocellular reticular formation (RPcvm) and in the caudal extension of RPcvm, the nucleus centralis dorsalis of the medulla oblongata, and the gigantocellular reticular formation (RGc). In a second series of experiments, WGA/HRP and BDA injections in these reticular areas were used to visualize afferent fibers and terminals in the SSp. The combination of the two types of experiments shows that RPcvm and RGc contain modest numbers of craniocervical premotor neurons. Because the reticular formation also contains jaw and tongue premotor neurons and receives a variety of sensory projections, the present results suggest that the medullary reticular formation plays a role in the coordination of complex movements (e.g., feeding). The pattern of afferent and efferent connections of the reticular formation is used to redefine its subdivisions in the myelencephalon of the mallard.
绿头鸭的脊髓上核（SSp）位于脊髓前端和脑干尾部，是一个运动核，它是腹角在前端的延续。它包含支配头颈部肌肉的部分运动神经元。向脊髓上核注射辣根过氧化物酶（HRP）和与HRP结合的小麦胚凝集素（WGA），用于定位延髓网状结构中的头颈部运动前神经元。将WGA和HRP的混合物（WGA/HRP）或生物素化葡聚糖胺（BDA）注射到不同的网状区域以验证结果。在小细胞网状结构（RPcvm）的腹内侧部分以及RPcvm的尾端延伸部分、延髓背侧中央核和巨细胞网状结构（RGc）中，双侧发现了少量的头颈部运动前神经元。在第二组实验中，向这些网状区域注射WGA/HRP和BDA，以观察脊髓上核中的传入纤维和终末。这两类实验的结合表明，RPcvm和RGc包含数量适中的头颈部运动前神经元。由于网状结构还包含下颌和舌部运动前神经元，并接受多种感觉投射，目前的结果表明，延髓网状结构在复杂运动（如进食）的协调中起作用。利用网状结构的传入和传出连接模式，对绿头鸭延髓中的网状结构分区进行了重新定义。
