Brodal P, Bjaalie J G
Department of Anatomy, University of Oslo, Norway.
Neurosci Res. 1992 Mar;13(2):83-118. doi: 10.1016/0168-0102(92)90092-q.
The pontine nuclei provide the cerebellar hemispheres with the majority of their mossy fiber afferents, and receive their main input from the cerebral cortex. Even though the vast majority of pontine neurons send their axons to the cerebellar cortex, and are contacted monosynaptically by (glutamatergic) corticopontine fibers, the information-processing taking place is not well understood. In addition to typical projection neurons, the pontine nuclei contain putative GABA-ergic interneurons and complex synaptic arrangements. The corticopontine projection is characterized by a precise but highly divergent terminal pattern. Large and functionally diverse parts of the cerebral cortex contribute; in the monkey the most notable exception is the almost total lack of projections from large parts of the prefrontal and temporal cortices. Within corticopontine projections from visual and somatosensory areas there is a de-emphasis of central vision and distal parts of the extremities as compared with other connections of these sensory areas. Subcorticopontine projections provide only a few percent of the total input to the pontine nuclei. Certain cell groups, such as the reticular formation, project in a diffuse manner whereas other nuclei, such as the mammillary nucleus, project to restricted pontine regions only, partially converging with functionally related corticopontine connections. The pontocerebellar projection is characterized by a highly convergent pattern, even though there is also marked divergence. Neurons projecting to a single cerebellar folium appear to be confined to a lamella-shaped volume in the pontine nuclei. The organization of the pontine nuclei suggests that they ensure that information from various, functionally diverse, parts of the cerebral cortex and subcortical nuclei are brought together and integrated in the cerebellar cortex.
脑桥核为小脑半球提供了大部分苔藓纤维传入纤维，并从大脑皮质接收主要输入。尽管绝大多数脑桥神经元将其轴突发送到小脑皮质，并与（谷氨酸能的）皮质脑桥纤维形成单突触联系，但其中发生的信息处理过程尚未得到很好的理解。除了典型的投射神经元外，脑桥核还包含假定的γ-氨基丁酸能中间神经元和复杂的突触排列。皮质脑桥投射的特点是具有精确但高度发散的终末模式。大脑皮质的大部分区域和功能各异的部分都有贡献；在猴子中，最显著的例外是前额叶和颞叶皮质的大部分区域几乎完全缺乏投射。在来自视觉和躯体感觉区域的皮质脑桥投射中，与这些感觉区域的其他连接相比，中央视觉和肢体远端部分的连接有所减弱。皮质下脑桥投射仅提供脑桥核总输入的百分之几。某些细胞群，如网状结构，以弥散方式投射，而其他核团，如乳头体核，仅投射到有限的脑桥区域，部分与功能相关的皮质脑桥连接汇聚。脑桥小脑投射的特点是高度汇聚模式，尽管也有明显的发散。投射到单个小脑小叶的神经元似乎局限于脑桥核中的一个薄片状区域。脑桥核的组织表明，它们确保来自大脑皮质和皮质下核团不同功能部分的信息在小脑皮质中汇聚并整合。
