Feil K, Herbert H
Department of Animal Physiology, University of Tübingen, Germany.
J Comp Neurol. 1995 Mar 20;353(4):506-28. doi: 10.1002/cne.903530404.
We examined the organization of somatosensory projections to the parabrachial (PB) and Kölliker-Fuse (KF) nuclei by employing the retrograde and anterograde axonal transport of Fluorogold and Phaseolus vulgaris-leucoagglutinin (PHA-L), respectively. Small PHA-L injections were made into different parts of the spinal trigeminal complex, including the paratrigeminal nucleus, and into different segments and laminae of the spinal dorsal horn. The subnuclear distribution of axonal labeling in the PB and KF was mapped with a camera lucida. Our results show that the somatosensory input to the PB and KF is highly organized. Neurons in the spinal trigeminal nuclei project predominantly to the KF and to the ventral portion of the external lateral PB. Neurons in the paratrigeminal nucleus project to the ventral lateral PB, the external medial PB, and to caudal aspects of the medial PB. These findings were supported by retrograde tracing experiments with Fluorogold. Spinal cord neurons located in the superficial dorsal horn (laminae I-II) of upper cervical segments project specifically to the ventral portion of the external lateral PB and, although more sparsely, to various other lateral PB nuclei. In contrast, neurons in the superficial dorsal horn of thoracic and lumbar spinal segments project mainly to the dorsal lateral and the central lateral PB. Finally, neurons in the lateral reticulated area and the lateral spinal nucleus of all spinal segments project almost exclusively to the internal lateral PB, whereas neurons in the respective nuclei of upper cervical segments also project to the KF. From our data we conclude that the somatosensory projections to the PB and KF are topographically organized. It is assumed that these pathways, which run from trigeminal and spinal neurons through the PB and KF to various forebrain, medullary, and spinal nuclei, form functionally different neural circuits that are involved in somatoautonomic processing.
我们分别通过荧光金逆行轴突运输和菜豆白细胞凝集素（PHA-L）顺行轴突运输，研究了躯体感觉投射至臂旁核（PB）和 Kölliker-Fuse 核（KF）的组织情况。将小剂量的 PHA-L 注射到脊髓三叉神经复合体的不同部位，包括三叉旁核，以及脊髓背角的不同节段和板层。用明视野显微镜绘制 PB 和 KF 中轴突标记的亚核分布。我们的结果表明，PB 和 KF 的躯体感觉输入高度有序。脊髓三叉神经核中的神经元主要投射至 KF 和外侧 PB 的腹侧部分。三叉旁核中的神经元投射至外侧 PB 的腹外侧、外侧 PB 的内侧以及内侧 PB 的尾侧部分。这些发现得到了荧光金逆行追踪实验的支持。位于颈上段脊髓背角浅层（I-II 板层）的神经元特异性投射至外侧 PB 的腹侧部分，尽管投射较为稀疏，但也投射至外侧 PB 的其他各个核团。相比之下，胸段和腰段脊髓背角浅层的神经元主要投射至背外侧 PB 和中央外侧 PB。最后，所有脊髓节段的外侧网状区域和外侧脊髓核中的神经元几乎全部投射至内侧 PB，而颈上段相应核团中的神经元也投射至 KF。根据我们的数据，我们得出结论，投射至 PB 和 KF 的躯体感觉是按拓扑结构组织的。据推测，这些从三叉神经和脊髓神经元经 PB 和 KF 至各种前脑、延髓和脊髓核团的通路，形成了参与躯体自主处理的功能不同的神经回路。
