■内嗅皮层已被证明参与陆地哺乳动物的高级认知功能。它可以分为两个主要区域:外侧内嗅区(LEA)和内侧内嗅区(MEA)。鉴于其认知能力的广泛证据,了解鲸目动物的结构组织尤为重要。本研究描述了宽吻海豚(Tursiopstruncatus,蒙塔古,1821),也许是研究最多的鲸目动物物种,也是海豚和其他小型鲸目动物的范例。
■处理了四个宽吻海豚\'内嗅皮质。为了获得内嗅皮层组织的精确概述,我们使用硫素染色来研究其层状和区域组织,和免疫过氧化物酶技术来研究三种最常用的钙结合蛋白(CBP)的免疫组织化学分布,CalbindinD-28k(CB),钙视网膜素(CR)和小清蛋白(PV)。内皮层厚度测量,对各层进行形态学和形态计量分析,并进行统计学比较。
■确定了LEA和MEA中的六个层。在层II和层III中观察到LEA和MEA之间的主要差异:LEA层II中的神经元比MEA层II中的神经元更致密且更大。此外,LEA中II层和III层之间的相对无细胞区,但不是在MEA,被观察到。三种CBPs的免疫组织化学分布,CB,CR和PV在每一层中是不同的。CR的免疫染色模式,在一边,和CB/PV,在另一边,似乎是以互补的方式分布的。PV和CB免疫染色在II和III层中尤其明显,而CR免疫反应性神经元分布在所有层,尤其是在第V层和第VI层中。免疫反应性由属于不同形态类别的神经元表达:所有CBPs在非锥体神经元中表达,但在锥体神经元中也发现了CB和CR。
■海豚内嗅皮层中的锥体和非锥体神经元的形态特征与其他物种的内嗅皮层中描述的相似,包括灵长类动物和啮齿动物。有趣的是,在灵长类动物中,啮齿动物,还有海豚,大多数含有CBP的神经元都存在于表层,但是大的CR-ir神经元在深层也很丰富。内嗅皮层的第II层和第III层包含产生穿孔通路的神经元,将大部分皮质信息传递到海马结构。从海马结构来看,相互投影指向内嗅皮层的深层,将信息分发到新皮层和皮层下区域。我们的数据显示,在海豚内嗅皮层,三种主要的CBPs标记了形态上异质的神经元组,它们可能参与了内嗅输入和输出途径之间的信息流。
UNASSIGNED: The entorhinal cortex has been shown to be involved in high-level cognitive functions in terrestrial mammals. It can be divided into two main areas: the lateral entorhinal area (LEA) and the medial entorhinal area (MEA). Understanding of its structural organization in cetaceans is particularly important given the extensive evidence for their cognitive abilities. The present study describes the cytoarchitectural and immunohistochemical properties of the entorhinal cortex of the bottlenose dolphin (Tursiops truncatus, Montagu, 1821), perhaps the most studied cetacean species and a paradigm for dolphins and other small cetaceans.
UNASSIGNED: Four bottlenose dolphins\' entorhinal cortices were processed. To obtain a precise overview of the organization of the entorhinal cortex we used thionin staining to study its laminar and regional organization, and immunoperoxidase technique to investigate the immunohistochemical distribution of three most commonly used calcium-binding proteins (CBPs), calbindin D-28k (CB), calretinin (CR) and parvalbumin (PV). Entorhinal cortex layers thickness were measured, morphological and morphometric analysis for each layer were conducted and statistically compared.
UNASSIGNED: Six layers in both the LEA and MEA were identified. The main difference between the LEA and the MEA is observed in layers II and III: the neurons in layer II of the LEA were denser and larger than the neurons in layer II of MEA. In addition, a relatively cell-free zone between layers II and III in LEA, but not in MEA, was observed. The immunohistochemical distribution of the three CBPs, CB, CR and PV were distinct in each layer. The immunostaining pattern of CR, on one side, and CB/PV, on the other side, appeared to be distributed in a complementary manner. PV and CB immunostaining was particularly evident in layers II and III, whereas CR immunoreactive neurons were distributed throughout all layers, especially in layers V and VI. Immunoreactivity was expressed by neurons belonging to different morphological classes: All CBPs were expressed in non-pyramidal neurons, but CB and CR were also found in pyramidal neurons.
UNASSIGNED: The morphological characteristics of pyramidal and non-pyramidal neurons in the dolphin entorhinal cortex are similar to those described in the entorhinal cortex of other species, including primates and rodents. Interestingly, in primates, rodents, and dolphins, most of the CBP-containing neurons are found in the superficial layers, but the large CR-ir neurons are also abundant in the deep layers. Layers II and III of the entorhinal cortex contain neurons that give rise to the perforant pathway, which conveys most of the cortical information to the hippocampal formation. From the hippocampal formation, reciprocal projections are directed back to the deep layer of the entorhinal cortex, which distributes the information to the neocortex and subcortical area. Our data reveal that in the dolphin entorhinal cortex, the three major CBPs label morphologically heterogeneous groups of neurons that may be involved in the information flow between entorhinal input and output pathways.