Bernstein Center for Computational Neuroscience, Humboldt University of Berlin, 10115 Berlin, Germany.
J Comp Neurol. 2012 Aug 1;520(11):2512-30. doi: 10.1002/cne.23053.
The Etruscan shrew, Suncus etruscus, is one of the smallest mammals. Etruscan shrews can recognize prey shape with amazing speed and accuracy, based on whisker-mediated tactile cues. Because of its small size, quantitative analysis of the Etruscan shrew cortex is more tractable than in other animals. To quantitatively assess the anatomy of the Etruscan shrew's brain, we sectioned brains and applied Nissl staining and NeuN (neuronal nuclei) antibody staining. On the basis of these stains, we estimated the number of neurons of 10 cortical hemispheres by using Stereoinvestigator and Neurolucida (MBF Bioscience) software. On average, the neuron number per hemisphere was found to be ~1 million. We also measured cortical surface area and found an average of 11.1 mm² (n = 7) and an average volume of 5.3 mm³ (n = 10) per hemisphere. We identified 13 cortical regions by cytoarchitectonic boundaries in coronal, sagittal, and tangential sections processed for Nissl substance, myelin, cytochrome oxidase, ionic zinc, neurofilaments, and vesicular glutamate transporter 2 (VGluT2). The Etruscan shrew is a highly tactile animal with a large somatosensory cortex, which contains a barrel field, but the barrels are much less clearly defined than in rodents. The anatomically derived cortical partitioning scheme roughly corresponds to physiologically derived maps of neocortical sensory areas.
伊特鲁里亚鼩鼱（Suncus etruscus）是最小的哺乳动物之一。伊特鲁里亚鼩鼱能够基于触须介导的触觉线索，以惊人的速度和准确性识别猎物的形状。由于其体型小，因此定量分析伊特鲁里亚鼩鼱的大脑皮质比其他动物更容易。为了定量评估伊特鲁里亚鼩鼱大脑的解剖结构，我们对大脑进行切片，并应用尼氏染色和神经元核（NeuN）抗体染色。基于这些染色，我们使用 Stereoinvestigator 和 Neurolucida（MBF Bioscience）软件估计了 10 个大脑半球的神经元数量。平均而言，每个半球的神经元数量约为 100 万。我们还测量了皮质表面积，发现每个半球的平均面积为 11.1 平方毫米（n = 7），平均体积为 5.3 立方毫米（n = 10）。我们通过 Nissl 物质、髓鞘、细胞色素氧化酶、离子锌、神经丝和囊泡谷氨酸转运体 2（VGluT2）在冠状、矢状和切线切片中识别出 13 个皮质区域。伊特鲁里亚鼩鼱是一种高度触觉动物，具有较大的体感皮质，其中包含一个桶状皮层区，但桶状区的定义比啮齿动物的要模糊得多。解剖学衍生的皮质分区方案大致对应于新皮层感觉区的生理学衍生图谱。
