Department of Anthropology, The George Washington University, Washington, DC 20052, USA.
Am J Hum Biol. 2011 Jan-Feb;23(1):22-8. doi: 10.1002/ajhb.21135.
Von Economo neurons (VENs) are defined by their thin, elongated cell body and long dendrites projecting from apical and basal ends. These distinctive neurons are mostly present in anterior cingulate (ACC) and fronto-insular (FI) cortex, with particularly high densities in cetaceans, elephants, and hominoid primates (i.e., humans and apes). This distribution suggests that VENs contribute to specializations of neural circuits in species that share both large brain size and complex social cognition, possibly representing an adaptation to rapidly relay socially-relevant information over long distances across the brain. Recent evidence indicates that unique patterns of protein expression may also characterize VENs, particularly involving molecules that are known to regulate gut and immune function.
In this study, we used quantitative stereologic methods to examine the expression of three such proteins that are localized in VENs-activating-transcription factor 3 (ATF3), interleukin 4 receptor (IL4Rα), and neuromedin B (NMB). We quantified immunoreactivity against these proteins in different morphological classes of ACC layer V neurons of hominoids.
Among the different neuron types analyzed (pyramidal, VEN, fork, enveloping, and other multipolar), VENs showed the greatest percentage that displayed immunostaining. Additionally, a higher proportion of VENs in humans were immunoreactive to ATF3, IL4Rα, and NMB than in other apes. No other ACC layer V neuron type displayed a significant species difference in the percentage of immunoreactive neurons.
These findings demonstrate that phylogenetic variation exists in the protein expression profile of VENs, suggesting that humans might have evolved biochemical specializations for enhanced interoceptive sensitivity.
冯·埃科诺莫神经元（VENs）的特征是其细长的细胞体和从顶端和基底端伸出的长树突。这些独特的神经元主要存在于前扣带皮层（ACC）和额岛皮层（FI）中，在鲸类动物、大象和人科灵长类动物（即人类和猿类）中密度特别高。这种分布表明，VENs 有助于具有大的大脑和复杂的社会认知的物种的神经回路的专业化，可能代表了一种适应，以在大脑中长距离快速传递与社会相关的信息。最近的证据表明，VENs 的表达模式也可能具有独特性，特别是涉及到已知调节肠道和免疫功能的分子。
在这项研究中，我们使用定量立体学方法来研究三种定位于 VENs 的蛋白质的表达，即激活转录因子 3（ATF3）、白细胞介素 4 受体（IL4Rα）和神经调节素 B（NMB）。我们在人科灵长类动物的 ACC 层 V 神经元的不同形态类群中对这些蛋白质的免疫反应性进行了量化。
在分析的不同神经元类型（锥体、VEN、叉形、包裹和其他多极）中，VENs 显示出具有免疫染色的最大百分比。此外，与其他猿类相比，人类的 VENs 对 ATF3、IL4Rα 和 NMB 的免疫反应性比例更高。在 ACC 层 V 神经元的其他类型中，没有显示出对物种差异有显著影响的免疫反应性神经元的百分比。
这些发现表明，VENs 的蛋白质表达谱存在种系变异，这表明人类可能已经进化出了增强内脏敏感性的生化特化。
