Alisky J M, Tolbert D L
Department of Anatomy and Neurobiology, St Louis University School of Medicine, MO 63104, USA.
Neuroscience. 1997 Sep;80(2):373-88. doi: 10.1016/s0306-4522(97)00082-1.
The convergence/divergence of mossy fibre afferent projections to the cerebellar anterior lobe from a single lumbar segment, from adjacent or widely separated lower thoracic and lumbar segments, and finally from the lower thoracic-upper lumbar spinal cord and the brainstem cuneate nuclei was quantitatively analysed in adult rats. Spinal and cuneate mossy fibre terminals were differentially labelled with biotinylated dextran amine and cholera toxin subunit B, immunohistochemically identified in the same histological sections, and their spatial distributions quantitatively plotted in computer reconstructions of the unfolded anterior lobe cortex. Afferent convergence was quantified by calculating the number of biotinylated dextran amine-labelled terminals that radially overlapped with cholera toxin-labelled terminals at points on the unfolded cortical map that represented theoretical Purkinje cells. Spino- and cuneocerebellar mossy fibre terminals are organized in patches that are oriented in parasagittally-oriented stripes or transversely oriented bands. Afferent convergence was greatest following biotinylated dextran amine and cholera toxin injections in the same or adjacent spinal lumbar segments (60 and 52%, respectively). When biotinylated dextran amine and cholera toxin were injected in a single segment differentially labelled terminals appeared randomly intermingled in common patches. There was a trend for terminals labelled from adjacent lumbar segments to be more segregated in the patches. Segmentally separated biotinylated dextran amine and cholera toxin spinal cord injections (four lumbar segments) resulted in clearly segregated (80%) biotinylated dextran amine from cholera toxin-labelled terminal patches or patches with distinct divergence of the differentially labelled terminals in the patch. Cuneocerebellar terminals labelled with biotinylated dextran amine were located in patches, stripes, and bands spatially segregated from terminal patches, stripes, and bands of cholera toxin-labelled spinal afferents except at their immediate borders where some radial overlap occurred (9-22%). These anatomical findings for a fractured somatotopy of spinal and cuneate inputs to the cerebellar anterior lobe complement neurophysiological findings for a very similar pattern of organization of cutaneous inputs to the posterior lobe, and are discussed in light of potential mechanisms for anterior lobe processing of somatosensory information.
在成年大鼠中，对来自单个腰段、相邻或广泛分离的下胸段和腰段，以及最终来自下胸段 - 上腰段脊髓和脑干楔束核的苔藓纤维传入投射至小脑前叶的汇聚/发散情况进行了定量分析。脊髓和楔束苔藓纤维终末分别用生物素化葡聚糖胺和霍乱毒素B亚基进行差异标记，在同一组织学切片中通过免疫组织化学鉴定，并在展开的前叶皮质的计算机重建中对它们的空间分布进行定量绘制。通过计算在展开的皮质图谱上代表理论浦肯野细胞的点处，与霍乱毒素标记的终末径向重叠的生物素化葡聚糖胺标记的终末数量，来量化传入汇聚。脊髓和楔小脑苔藓纤维终末组织成斑块，这些斑块以矢状旁向条纹或横向带的形式排列。在同一或相邻腰段注射生物素化葡聚糖胺和霍乱毒素后，传入汇聚最大（分别为60%和52%）。当在单个节段注射生物素化葡聚糖胺和霍乱毒素时，差异标记的终末随机混合在共同的斑块中。来自相邻腰段标记的终末在斑块中有更明显分离的趋势。节段性分离的生物素化葡聚糖胺和霍乱毒素脊髓注射（四个腰段）导致生物素化葡聚糖胺与霍乱毒素标记的终末斑块明显分离（80%），或在斑块中差异标记的终末有明显的发散。用生物素化葡聚糖胺标记的楔小脑终末位于斑块、条纹和带中，在空间上与霍乱毒素标记的脊髓传入终末的斑块、条纹和带分隔开，除了在它们紧邻的边界处有一些径向重叠（9 - 22%）。这些关于脊髓和楔束输入到小脑前叶的躯体定位断裂的解剖学发现，补充了关于皮肤输入到后叶的非常相似的组织模式的神经生理学发现，并根据躯体感觉信息在前叶处理的潜在机制进行了讨论。
