The claustrum is a bilateral subcortical nucleus situated between the insular cortex and the striatum in the brain of all mammals. It consists of two embryologically distinct subdivisions - dorsal and ventral claustrum. The claustrum has high connectivity with various areas of the cortex, subcortical and allocortical structures. It has long been suggested that the various claustral connections have different types of synaptic contacts at the claustral neurons. However, to the best of our knowledge, the literature data on the ultrastructural organization of the different types of synaptic contacts in the dorsal claustrum are very few. Therefore, the aim of our study was to observe and describe the synaptic organization of the dorsal claustrum in the cat. We used a total of 10 adult male cats and conducted an ultrastructural study under a transmission electron microscope as per established protocol. We described a multitude of dendritic spines, which were subdivided into two types - with and without foot processes. Based on the size and shape of the terminal boutons, the quantity and distribution of vesicles and the characteristic features of the active synaptic zone, we described six types of synaptic boutons, most of which formed asymmetrical synaptic contacts. Furthermore, we reported the presence of axo-dendritic, axo-somatic, dendro-dendritic and axo-axonal synapses. The former two likely represent the morphological substrate of the corticoclaustral pathway, while the remaining two types have the ultrastructural features of inhibitory synapses, likely forming a local inhibitory circuit in the claustrum. In conclusion, the present study shares new information about the neuropil of the claustrum and proposes a systematic classification of the types of synaptic boutons and contacts observed in the dorsal claustrum of the cat, thus supporting its key and complex role as a structure integrating various information within the brain.

中文翻译：

---

猫背锁骨的超微结构。二。突触组织。

锁骨是位于所有哺乳动物大脑中的岛状皮层和纹状体之间的双侧皮质下核。它由两个在胚胎学上不同的细分组成-背侧和腹侧锁骨。锁骨与皮层，皮层下和分配结构的各个区域具有高度的连通性。长期以来，人们一直认为各种clastral连接在clastral神经元处具有不同类型的突触接触。然而，就我们所知，背锁骨中不同类型的突触接触的超微结构的文献资料很少。因此，我们研究的目的是观察和描述猫背锁骨的突触组织。我们总共使用了10只成年雄性猫，并按照既定规程在透射电子显微镜下进行了超微结构研究。我们描述了许多树突棘，它们分为两种类型-有脚突和没有脚突。根据末梢突突的大小和形状，囊泡的数量和分布以及活性突触区的特征，我们描述了六种类型的突触突突，其中大多数形成了不对称的突触接触。此外，我们报告了轴突，树突状体，树突状树突和轴突轴突突的存在。前两种可能代表皮质尾骨途径的形态学底物，而其余两种则具有抑制性突触的超微结构特征，可能在锁骨上形成局部抑制回路。总之，本研究分享了有关锁骨神经丛的新信息，并提出了对猫背锁骨中观察到的突触钮扣和接触类型的系统分类，从而支持了其作为整合各种信息的结构的关键而复杂的作用。在大脑内。