Hakeem Atiya Y, Hof Patrick R, Sherwood Chet C, Switzer Robert C, Rasmussen L E L, Allman John M
Division of Biology, California Institute of Technology, Pasadena, California 91125, USA.
Anat Rec A Discov Mol Cell Evol Biol. 2005 Nov;287(1):1117-27. doi: 10.1002/ar.a.20255.
We acquired magnetic resonance images of the brain of an adult African elephant, Loxodonta africana, in the axial and parasagittal planes and produced anatomically labeled images. We quantified the volume of the whole brain (3,886.7 cm3) and of the neocortical and cerebellar gray and white matter. The white matter-to-gray matter ratio in the elephant neocortex and cerebellum is in keeping with that expected for a brain of this size. The ratio of neocortical gray matter volume to corpus callosum cross-sectional area is similar in the elephant and human brains (108 and 93.7, respectively), emphasizing the difference between terrestrial mammals and cetaceans, which have a very small corpus callosum relative to the volume of neocortical gray matter (ratio of 181-287 in our sample). Finally, the elephant has an unusually large and convoluted hippocampus compared to primates and especially to cetaceans. This may be related to the extremely long social and chemical memory of elephants.
我们获取了一头成年非洲象（Loxodonta africana）大脑在轴位和矢状旁位平面的磁共振图像，并生成了带有解剖学标注的图像。我们对整个大脑（3886.7立方厘米）以及新皮层、小脑的灰质和白质体积进行了量化。大象新皮层和小脑的白质与灰质比例与这种大小的大脑预期相符。大象和人类大脑中，新皮层灰质体积与胼胝体横截面积的比例相似（分别为108和93.7），这突出了陆生哺乳动物与鲸类动物之间的差异，鲸类动物的胼胝体相对于新皮层灰质体积非常小（在我们的样本中比例为181 - 287）。最后，与灵长类动物尤其是鲸类动物相比，大象的海马体异常大且卷曲。这可能与大象极其漫长的社会和化学记忆有关。
