Kisvárday Z F, Martin K A, Whitteridge D, Somogyi P
J Comp Neurol. 1985 Nov 8;241(2):111-37. doi: 10.1002/cne.902410202.
Light and electron microscopic quantitative analysis was carried out on a type of neuron intracellularly filled with horseradish peroxidase. Two cells were studied in area 17, one of which was injected intra-axonally, and its soma was not recovered. One cell was studied in area 18. The two somata were on the border of layers IVa/b; they were radially elongated and received synapses from numerous large boutons with round synaptic vesicles. The dendrites were smooth and remained largely in layer IV. The cells can be recognised on the basis of their axonal arbor, which was restricted to layer IV (90-95% of boutons) with minor projections to layers III, V, and VI. Many of the large, bulbous boutons contacted neuronal somata, short collaterals often forming "claw"-like configurations around cells. The name "clutch cell" is suggested to delineate this type of neuron from other aspiny multipolar cells. Computer-assisted reconstruction of the axon showed that in layer IV the axons occupied a rectangular area about 300 X 500 microns, elongated anteroposteriorly in area 17 and mediolaterally in area 18. The distributions of synaptic boutons and postsynaptic cells were patchy within this area. A total of 321 boutons were serially sectioned in area 17. The boutons formed type II synaptic contacts. The postsynaptic targets were somata (20-30%), dendritic shafts (35-50%), spines (30%), and rarely axon initial segments. Most of the postsynaptic somata tested were not immunoreactive for GABA and their fine structural features suggest that they are spiny stellate, star pyramidal, and pyramidal neurons. The characteristics of most of the postsynaptic dendrites and spines also suggest that they belong to these spiny neurons. A few of the postsynaptic dendrites and somata exhibited characteristics of cells with smooth dendrites and these somata were immunoreactive for GABA. It is suggested that clutch cells are inhibitory interneurons exerting their effect mainly on layer IV spiny neurons in an area localised perhaps to a single ocular dominance column. The specific laminar location of the axons of clutch cell also suggests that they may be associated with the afferent terminals of lateral geniculate nucleus cells, and could thus be responsible for generating some of the selective properties of neurons of the first stage of cortical processing.
对一种细胞内填充辣根过氧化物酶的神经元进行了光镜和电镜定量分析。在17区研究了两个细胞，其中一个是轴突内注射，其胞体未回收。在18区研究了一个细胞。两个胞体位于IVa/b层的边界；它们呈放射状拉长，接受来自许多带有圆形突触小泡的大型终扣的突触。树突光滑，主要位于IV层。这些细胞可根据其轴突分支来识别，轴突分支局限于IV层（90 - 95%的终扣），向III、V和VI层有少量投射。许多大型的球状终扣与神经元胞体接触，短的侧支常常在细胞周围形成“爪”状结构。建议将这种神经元命名为“扣合细胞”，以将其与其他无棘多极细胞区分开来。计算机辅助的轴突重建显示，在IV层，轴突占据一个约300×500微米的矩形区域，在17区沿前后方向拉长，在18区沿内外侧方向拉长。在这个区域内，突触终扣和突触后细胞的分布是斑片状的。在17区共对321个终扣进行了连续切片。这些终扣形成II型突触联系。突触后靶点是胞体（20 - 30%）、树突干（35 - 50%）、棘（30%），很少是轴突起始段。大多数测试的突触后胞体对GABA无免疫反应，其精细结构特征表明它们是有棘星状、星形锥体细胞和锥体细胞。大多数突触后树突和棘的特征也表明它们属于这些有棘神经元。少数突触后树突和胞体表现出树突光滑的细胞特征，这些胞体对GABA有免疫反应。有人认为扣合细胞是抑制性中间神经元，主要在可能局限于单个眼优势柱的区域对IV层有棘神经元发挥作用。扣合细胞轴突的特定层位位置也表明它们可能与外侧膝状体细胞核细胞的传入终末有关，因此可能负责产生皮质处理第一阶段神经元的一些选择性特性。
