Distribution of corticospinal neurons with collaterals to lower brain stem reticular formation in cat
Distribution of corticospinal neurons with collaterals to lower brain stem reticular formation in cat
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猫皮质脊髓神经元的侧络分布对降低脑干网状形成的影响
DOI：
10.1007/bf00235823
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发表时间：
2004
影响因子：
2
通讯作者：
H. Kuypers
中科院分区：
文献类型：
--
作者：
Dr. K. Keizer;H. Kuypers
摘要采用荧光逆行双标记技术测定猫感觉运动皮层皮质脊髓神经元是否向下脑干网状结构分布侧枝。本研究采用荧光示踪剂核黄和二胺黄2HCl与Fast Blue联合使用。一种示踪剂单侧注射于脊髓，另一种示踪剂同侧注射于球内侧网状结构。研究逆行标记神经元在对侧半球的分布。在感觉运动皮层中发现了大量的神经元，它们分别来自脊髓和脑干的双重标记。这些分支神经元集中在第4区前内侧和毗邻的第6区外侧。在这个区域，来自脑干的皮质脊髓神经元被双重标记的百分比从5%的外侧到30%的内侧不等。在两只猫中，通过HRP的顺行运输，证明了来自该区域的皮质球纤维（必须包括皮质脊髓侧支）分布到下脑干的网状结构。鉴于双标记神经元集中在运动皮层的前部，这些分支神经元极有可能参与了颈部、背部和肩部运动的控制。这种控制可能通过两种途径发挥作用，即通过与脊髓中间神经元的直接皮质-脊髓连接，以及通过皮质纤维与球网状结构建立的间接皮质-网状脊髓连接。目前的研究结果表明，这种双重控制可能是由同一个细胞施加的。
SummaryThe fluorescent retrograde double-labeling technique has been used to determine whether corticospinal neurons in the cat sensorimotor cortex distribute collaterals to the lower brain stem reticular formation. In this study the fluorescent tracers Nuclear Yellow and Diamidino Yellow 2HCl were used in combination with Fast Blue. One tracer was injected unilaterally in the spinal cord and the other was injected ipsilaterally in the bulbar medial reticular formation. The distribution of the retrogradely labeled neurons was studied in the contralateral hemisphere. In the sensorimotor cortex a large population of neurons was found which were labeled from the spinal cord and were double-labeled from the brain stem. These branching neurons were concentrated in the rostromedial part of area 4 and the adjoining lateral part of area 6. In this region the percentages of corticospinal neurons which were double-labeled from the brain stem ranged from 5% laterally to 30% medially. In two cats it was demonstrated by means of the anterograde transport of HRP that the corticobulbar fibers from this region which must include the corticospinal collaterals are distributed to the reticular formation of the lower brain stem. In view of the fact that the double-labeled neurons are concentrated in the anterior part of the motor cortex, those branching neurons are in all likelihood involved in the control of neck, back and shoulder movements. This control is probably exerted by way of two routes i.e. by way of the direct corticospinal connections to spinal interneurons, and by way of the indirect cortico-reticulospinal connections established by the cortical fibers to the bulbar reticular formation. The present findings suggest that this dual control may be exerted by one and the same cell.