THALAMIC AFFERENTS OF THE RAT BARREL CORTEX - A LIGHT-MICROSCOPIC AND ELECTRON-MICROSCOPIC STUDY USING PHASEOLUS-VULGARIS LEUKOAGGLUTININ AS AN ANTEROGRADE TRACER
THALAMIC AFFERENTS OF THE RAT BARREL CORTEX - A LIGHT-MICROSCOPIC AND ELECTRON-MICROSCOPIC STUDY USING PHASEOLUS-VULGARIS LEUKOAGGLUTININ AS AN ANTEROGRADE TRACER
复制标题
DOI：
10.3109/08990229309028819
复制
发表时间：
1993-01-01
影响因子：
0.9
通讯作者：
LIN, RCS
中科院分区：
文献类型：
--
作者：
LU, SM;LIN, RCS
用顺行示踪剂菜豆白细胞凝集素（PHA-L）和辣根过氧化物酶（HRP）在光镜和电镜水平上研究了大鼠初级体感皮层（SI）后内侧桶子区（PMBSF）的丘脑皮质传入。PMBSF，也称为桶皮质，可以根据细胞结构特征分为桶区和桶间区。限制注射局限于腹后内侧（VPM）或吻侧部分的后（POM）核，使我们能够研究和比较其投射模式的桶皮质。我们发现，interbarrel区域只接受来自POM的输入，而桶区域接受来自POM和VPM的输入。这两个投影的层流分布在很大程度上是分离的。在VPM中注入PHA-L或HRP后，在第VI层和桶区的第IV层至第I层中发现标记的钮扣样分泌物，其中第IV层中的浓度最高。另一方面，在Pom内注入PHA-L或HRP后，标记的钮扣样突触分布于管间区的上层V至I层，以及管区的V层和I层。超微结构分析表明，VPM和Pom通路的标记bouton样的突触与皮层神经元形成突触接触，并且这些接触是不对称的。因此，VPM和POM的预测是相互补充的桶皮质，并一起提供丘脑输入的桶和interbarrel地区的大多数层。VPM和Pom投射在桶状皮层中的不同终止模式表明它们可能参与不同类型的皮层处理。此外，我们目前的研究结果可能提供了两个平行的丘脑皮质通路，以前的生理研究表明，每个都与特定的亚模态的躯体信息的解剖学基础。
Anterograde tracers, Phaseolus vulgaris leucoagglutinin (PHA-L) and horseradish peroxidase (HRP), were used to study the thalamocortical afferents of the posteromedial barrel subfield (PMBSF) in rat primary somatosensory cortex (SI) at both light- and electron-microscopic levels. The PMBSF, also known as the barrel cortex, can be subdivided into barrel and interbarrel areas on the basis of cytoarchitectonic characteristics. Restricted injections confined to either the ventroposterior medial (VPM) or the rostral part of the posterior (Pom) nucleus allowed us to study and compare their projection patterns to the barrel cortex. We found that the interbarrel area receives inputs exclusively from the Pom, whereas the barrel area receives inputs from both the Pom and VPM. The laminar distributions of these two projections are largely segregated. After an injection of PHA-L or HRP into the VPM, labeled bouton-like swellings are found in layer VI and in layers IV through I of the barrel area, with the highest concentration in layer IV. On the other hand, after an injection of PHA-L or HRP into the Pom, labeled bouton-like swellings are distributed from upper layer V to layer I of the interbarrel area, as well as in layers V and I of the barrel area. Ultrastructural analysis showed that labeled bouton-like swellings of the VPM and the Pom pathways make synaptic contacts onto cortical neurons, and that these contacts are asymmetrical. Therefore, the VPM and the Pom projections are complementary to each other in the barrel cortex, and together they provide thalamic inputs to most layers of both the barrel and interbarrel areas. The differential patterns of terminations of the VPM and the Pom projections in the barrel cortex suggest that they may be involved in different types of cortical processing. Furthermore, our present findings may provide the anatomical basis for two parallel thalamocortical pathways, which previous physiological studies have indicated are each concerned with particular submodalities of somatic information.