Neuhuber W L, Zenker W
Institute of Anatomy, University of Zürich, Switzerland.
J Comp Neurol. 1989 Feb 8;280(2):231-53. doi: 10.1002/cne.902800206.
The projections of primary afferents from rostral cervical segments to the brainstem and the spinal cord of the rat were investigated by using anterograde and transganglionic transport techniques. Projections from whole spinal ganglia were compared with those from single nerves carrying only exteroceptive or proprioceptive fibers. Injections of horseradish peroxidase (HRP) or wheat germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) were performed into dorsal root ganglia C2, C3, and C4. Free HRP was applied to the cut dorsal rami C2 and C3, greater occipital nerve, sternomastoid nerve, and to the C1/2 anastomosis, which contains afferents from suboccipital muscles and the atlanto-occipital joint. WGA-HRP injections into ganglia C7 and L5 were performed for comparative purposes. Injections of WGA-HRP or free HRP into rostral cervical dorsal root ganglia and HRP application to C2 and C3 dorsal rami produced labeling in dorsal and ventral horns at the level of entrance, the central cervical nucleus, and in external and main cuneate nuclei. From axons ascending to pontine and descending to upper thoracic spinal levels, medial collaterals were distributed to medial and descending vestibular, perihypoglossal and solitary nuclei, and the intermediate zone and Clarke's nucleus dorsalis in the spinal cord. Lateral collaterals projected mainly to the trigeminal subnucleus interpolaris and to lateral spinal laminae IV and V. Results from HRP application to single peripheral nerves indicated that medial collaterals were almost exclusively proprioceptive, whereas lateral collaterals were largely exteroceptive with a contribution from suboccipital proprioceptive fibers. WGA-HRP injections into dorsal root ganglia C7 and L5 failed to produce significant labeling within vestibular and periphypoglossal nuclei, although they demonstrated classical projection sites within the brainstem and spinal cord. The consistent collateralisation pattern of rostral cervical afferents along their whole rostrocaudal course enables them to contact a variety of precerebellar, vestibulospinal, and preoculomotor neurons. These connections reflect the well-known significance of proprioceptive neck afferents for the control of posture, head position, and eye movements.
采用顺行和跨神经节运输技术，研究了大鼠延髓颈段初级传入纤维向脑干和脊髓的投射。将整个脊神经节的投射与仅携带外感受性或本体感受性纤维的单根神经的投射进行了比较。将辣根过氧化物酶（HRP）或小麦胚凝集素-辣根过氧化物酶复合物（WGA-HRP）注入颈背根神经节C2、C3和C4。将游离HRP应用于切断的颈2和颈3背支、枕大神经、胸锁乳突肌神经以及包含来自枕下肌和寰枕关节传入纤维的C1/2吻合处。为了进行比较，将WGA-HRP注入神经节C7和L5。将WGA-HRP或游离HRP注入延髓颈段背根神经节以及将HRP应用于颈2和颈3背支，在纤维进入水平的背角和腹角、颈中央核以及楔外核和楔主核中产生了标记。从上升到脑桥和下降到上胸段脊髓水平的轴突发出的内侧侧支分布到内侧和下行前庭核、舌下神经周核和孤束核，以及脊髓的中间带和背侧克拉克核。外侧侧支主要投射到三叉神经极间亚核以及脊髓外侧板层IV和V。将HRP应用于单根外周神经的结果表明，内侧侧支几乎完全是本体感受性的，而外侧侧支在很大程度上是外感受性的，枕下本体感受性纤维也有一定贡献。将WGA-HRP注入背根神经节C7和L5，虽然在前庭核和舌下神经周核内未产生明显标记，但在脑干和脊髓内显示出经典的投射部位。延髓颈段传入纤维在其整个头尾方向行程中一致的侧支模式，使它们能够与多种小脑前、前庭脊髓和动眼神经前神经元建立联系。这些连接反映了本体感受性颈部传入纤维对姿势、头部位置和眼球运动控制的众所周知的重要性。
