Ogren M P, Hendrickson A E
J Comp Neurol. 1979 Nov 1;188(1):147-78. doi: 10.1002/cne.901880112.
Previous light microscopic studies of Macaca pulvinar have demonstrated that both the inferior and adjacent portion of the lateral pulvinar subdivisions are reciprocally connected to the entire occipital lobe, including striate cortex. They differ in that inferior but not lateral pulvinar receives a projection from the superficial layers of the superior colliculus. In this study, the internal organization of these two subdivisions in compared by relating light microscopic Golgi morphology to the synaptic organization observed by electron microscopy. The Golgi impregnated neurons in inferior and lateral pulvinar are typical of other thalamic nuclei and are not qualitatively different in the two subdivisions. Projections neurons (PN) vary in cell body (15--40 micrometers) and dendritic tree (150--600 micrometers) diameters but bear the same varieties of dendritic appendages; spine-like, hair-like, and knot-like. Local circuit neurons (LCN) have smaller cell body diameters (10--20 micrometers) but can have very large dendritic field diameters (150--600 micrometers). They are best distinguished from PNs by their elaborate dendritic appendages, which have been identified as pre-synaptic dendrites in the EM. LCN axons are infrequently seen. In the EM both subdivisions contain four types of synaptic terminals. RS and RL terminal both contain round symaptic vesicles and make asymmetric synaptic contacts, but are subdivided on the basis of small (RS = 0.09 micrometers) versus large (RL = 2.2 micrometers) cross sectional diameters and organelle content. RLs contact larger caliber dendrites and frequently form synaptic complexes with presynaptic dendrites of LCNs, while RSs contact fine caliber dendrites and rarely take part in synaptic complexes. F terminal and P boutons both contain flat and pleomorphis vesicles and make symmetric synaptic contacts. They are characterized by vesicle number and cytoplasmic density. Fs are infrequently observed in pulvinar compared to P boutons and are of uncertain origin. P boutons can be equated with LCN dendritic appendages and have been identified as pre-synaptic dendrites. The quantitative distribution of each type is very similar in both subdivisions, avveraging RS 85%, RL 5%, F 0.3%, P 8% and unidentified 2%.
先前对猕猴枕核的光学显微镜研究表明，外侧枕核亚区的下部及其相邻部分与整个枕叶，包括纹状皮质，存在相互连接。它们的不同之处在于，外侧枕核的下部而非外侧部分接受上丘表层的投射。在本研究中，通过将光学显微镜下的高尔基形态学与电子显微镜观察到的突触组织相关联，对这两个亚区的内部结构进行了比较。在外侧枕核下部和外侧，经高尔基染色的神经元是典型的丘脑核神经元，在这两个亚区在性质上并无差异。投射神经元（PN）的细胞体直径（15 - 40微米）和树突直径（150 - 600微米）各不相同，但都具有相同种类的树突附属物，即棘状、毛状和结状。局部回路神经元（LCN）的细胞体直径较小（10 - 20微米），但其树突野直径可能非常大（150 - 600微米）。它们与投射神经元的最佳区别在于其复杂的树突附属物，在电子显微镜下已被鉴定为突触前树突。很少能看到局部回路神经元的轴突。在电子显微镜下，这两个亚区都包含四种类型的突触终末。RS和RL终末都含有圆形突触小泡，并形成不对称突触联系，但根据较小（RS = 0.09微米）与较大（RL = 2.2微米）的横截面积和细胞器含量进行细分。RL终末与较粗的树突接触，并经常与局部回路神经元的突触前树突形成突触复合体，而RS终末与细径树突接触，很少参与突触复合体的形成。F终末和P小体都含有扁平的和多形性小泡，并形成对称突触联系。它们的特征在于小泡数量和细胞质密度。与P小体相比，在枕核中很少观察到F终末，其起源尚不确定。P小体可等同于局部回路神经元的树突附属物，并已被鉴定为突触前树突。这两种亚区中每种类型的定量分布非常相似，平均RS为85%，RL为5%，F为0.3%，P为8%，未识别的为2%。
