Wu Xuanjing, Sarpong Gideon A, Zhang Jingyun, Sugihara Izumi
Department of Systems Neurophysiology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
Neurobiology Research Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.
Heliyon. 2023 Mar 9;9(4):e14352. doi: 10.1016/j.heliyon.2023.e14352. eCollection 2023 Apr.
The massive axonal projection from the cerebrum to the cerebellum through the pontine nuclei supports the cerebrocerebellar coordination of motor and nonmotor functions. However, the cerebrum and cerebellum have distinct patterns of functional localization in their cortices. We addressed this issue by bidirectional neuronal tracing from 22 various locations of the pontine nuclei in the mouse in a comprehensive manner. Cluster analyses of the distribution patterns of labeled cortical pyramidal cells and cerebellar mossy fiber terminals classified all cases into six groups located in six different subareas of the pontine nuclei. The lateral (insular), mediorostral (cingulate and prefrontal), and caudal (visual and auditory) cortical areas of the cerebrum projected to the medial, rostral, and lateral subareas of the pontine nuclei, respectively. These pontine subareas then projected mainly to the crus I, central vermis, and paraflocculus divergently. The central (motor and somatosensory) cortical areas projected to the centrorostral, centrocaudal and caudal subareas of the pontine nuclei, which then projected mainly to the rostral and caudal lobules with a somatotopic arrangement. The results indicate a new pontine nuclei-centric view of the corticopontocerebellar projection: the generally parallel corticopontine projection to pontine nuclei subareas is relayed to the highly divergent pontocerebellar projection terminating in overlapping specific lobules of the cerebellum. Consequently, the mode of the pontine nuclei relay underlies the cerebellar functional organization.
从大脑通过脑桥核向小脑的大量轴突投射支持了运动和非运动功能的大脑小脑协调。然而，大脑和小脑在其皮质中具有不同的功能定位模式。我们通过全面地从小鼠脑桥核的22个不同位置进行双向神经元追踪来解决这个问题。对标记的皮质锥体细胞和小脑苔藓纤维终末的分布模式进行聚类分析，将所有病例分为位于脑桥核六个不同亚区的六组。大脑的外侧（岛叶）、嘴侧中部（扣带回和前额叶）和尾侧（视觉和听觉）皮质区域分别投射到脑桥核的内侧、嘴侧和外侧亚区。这些脑桥亚区然后分别发散地主要投射到小脑脚I、中央蚓部和旁绒球。中央（运动和躯体感觉）皮质区域投射到脑桥核的中央嘴侧、中央尾侧和尾侧亚区，这些亚区然后主要以躯体定位排列投射到嘴侧和尾侧小叶。结果表明了一种以脑桥核为中心的皮质-脑桥-小脑投射的新观点：通常平行的皮质-脑桥投射到脑桥核亚区被中继到高度发散的脑桥-小脑投射，终止于小脑的重叠特定小叶。因此，脑桥核中继模式是小脑功能组织的基础。
