Patzke Nina, Olaleye Olatunbosun, Haagensen Mark, Hof Patrick R, Ihunwo Amadi O, Manger Paul R
School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg, 2193, South Africa.
Brain Struct Funct. 2014 Sep;219(5):1587-601. doi: 10.1007/s00429-013-0587-6. Epub 2013 Jun 2.
Elephants are thought to possess excellent long-term spatial-temporal and social memory, both memory types being at least in part hippocampus dependent. Although the hippocampus has been extensively studied in common laboratory mammalian species and humans, much less is known about comparative hippocampal neuroanatomy, and specifically that of the elephant. Moreover, the data available regarding hippocampal size of the elephant are inconsistent. The aim of the current study was to re-examine hippocampal size and provide a detailed neuroanatomical description of the hippocampus in the African elephant. In order to examine the hippocampal size the perfusion-fixed brains of three wild-caught adult male African elephants, aged 20-30 years, underwent MRI scanning. For the neuroanatomical description brain sections containing the hippocampus were stained for Nissl, myelin, calbindin, calretinin, parvalbumin and doublecortin. This study demonstrates that the elephant hippocampus is not unduly enlarged, nor specifically unusual in its internal morphology. The elephant hippocampus has a volume of 10.84 ± 0.33 cm³ and is slightly larger than the human hippocampus (10.23 cm(3)). Histological analysis revealed the typical trilaminated architecture of the dentate gyrus (DG) and the cornu ammonis (CA), although the molecular layer of the dentate gyrus appears to have supernumerary sublaminae compared to other mammals. The three main architectonic fields of the cornu ammonis (CA1, CA2, and CA3) could be clearly distinguished. Doublecortin immunostaining revealed the presence of adult neurogenesis in the elephant hippocampus. Thus, the elephant exhibits, for the most part, what might be considered a typically mammalian hippocampus in terms of both size and architecture.
大象被认为拥有出色的长期时空记忆和社会记忆，这两种记忆类型至少部分依赖于海马体。尽管海马体在常见的实验室哺乳动物物种和人类中已得到广泛研究，但对于海马体的比较神经解剖学，尤其是大象的海马体，人们所知甚少。此外，关于大象海马体大小的数据并不一致。本研究的目的是重新审视海马体大小，并对非洲象的海马体进行详细的神经解剖学描述。为了检查海马体大小，对三只20 - 30岁野生捕获的成年雄性非洲象的灌注固定大脑进行了MRI扫描。为了进行神经解剖学描述，对包含海马体的脑切片进行了尼氏染色、髓鞘染色、钙结合蛋白染色、钙视网膜蛋白染色、小白蛋白染色和双皮质素染色。这项研究表明，大象的海马体并没有过度增大，其内部形态也没有特别异常之处。大象海马体的体积为10.84 ± 0.33立方厘米，略大于人类海马体（10.23立方厘米）。组织学分析揭示了齿状回（DG）和海马角（CA）典型的三层结构，尽管与其他哺乳动物相比，齿状回的分子层似乎有额外的亚层。海马角的三个主要结构区域（CA1、CA2和CA3）可以清晰区分。双皮质素免疫染色显示大象海马体中存在成年神经发生。因此，就大小和结构而言，大象在很大程度上表现出可被认为是典型哺乳动物的海马体。
