Jürgens Uwe, Ehrenreich Ludwig
Department of Neurobiology, German Primate Center, Kellnerweg 4, 37077 Göttingen, Germany.
Brain Res. 2007 May 7;1148:90-5. doi: 10.1016/j.brainres.2007.02.020. Epub 2007 Feb 21.
The motor cortex of primates contains an area ("larynx area") which, when stimulated unilaterally, produces bilateral vocal fold adduction. In order to identify the pathway along which the cortical larynx area exerts its control on the laryngeal motoneurons, we have blocked excitatory neurotransmission in each of the main projection fields of the cortical larynx area and tested for the elicitability of vocal fold movements from this area in the squirrel monkey. Blocking was carried out by injection of the glutamate antagonist kynurenic acid. We found that injection into the dorsal reticular nucleus of the caudal medulla ipsilateral to the stimulation site blocked vocal fold movements bilaterally; injections invading major parts of the nucleus ambiguus blocked vocal fold movements exclusively ipsilateral to the injection site; and injections centered on the parvocellular reticular formation bordering the nucleus ambiguus blocked exclusively contralateral vocal fold movements. We conclude from this that the corticobulbar laryngeal control pathway synapses in the ipsilateral dorsal reticular nucleus and then divides into one component running directly to the ipsilateral nucleus ambiguus and a second component crossing to the contralateral nucleus ambiguus after having synapsed in the ipsilateral peri-ambigual reticular formation.
灵长类动物的运动皮层包含一个区域（“喉区”），当单侧刺激该区域时，会引起双侧声带内收。为了确定皮层喉区对喉运动神经元施加控制的途径，我们阻断了皮层喉区每个主要投射区域的兴奋性神经传递，并测试了松鼠猴该区域引发声带运动的能力。通过注射谷氨酸拮抗剂犬尿氨酸来进行阻断。我们发现，向刺激部位同侧延髓尾部的背侧网状核注射可双侧阻断声带运动；侵入疑核大部分区域的注射仅阻断注射部位同侧的声带运动；以与疑核相邻的小细胞网状结构为中心的注射仅阻断对侧声带运动。由此我们得出结论，皮质延髓喉控制通路在同侧背侧网状核形成突触，然后分为一个直接通向同侧疑核的分支和另一个在同侧疑核周围网状结构形成突触后交叉到对侧疑核的分支。
