Developmental organization of the mushroom bodies of Thermobia domestica (Zygentoma, Lepismatidae):: insights into mushroom body evolution from a basal insect
Developmental organization of the mushroom bodies of Thermobia domestica (Zygentoma, Lepismatidae):: insights into mushroom body evolution from a basal insect
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DOI：
10.1111/j.1525-142x.2005.05017.x
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发表时间：
2005-03-01
影响因子：
2.9
通讯作者：
Farris, SM
中科院分区：
文献类型：
--
作者：
Farris, SM
昆虫大脑的蘑菇体是感觉整合中心，其在学习和记忆中的作用得到了最好的研究。对新翅目昆虫蘑菇体结构和发育的研究揭示了保守的形态发生机制。蘑菇体神经母细胞连续产生形态不同的内在神经元（凯尼恩细胞）亚群，并通过离散的长入通道整合新生神经元，从而在蘑菇体的主要输出神经中形成基于年龄的模块化亚单位组织。为了确定这些是否代表了祖先的特征，本文评估了基生无翅昆虫热蝇（Thermobia domestica）的蘑菇体组织和发育。在这种昆虫中，由两个神经母细胞群的后代提供的单个花萼和三个垂直定向的裂片很容易识别。裂片被细分为15个球状细分（Trauben）。观察到终身神经发生，新生凯尼恩细胞的轴突通过向内生长的核心进入脑叶。Trauben细胞在发育过程中并不是逐渐出现的，这表明它们并不代表Kenyon细胞按顺序产生的亚群的分支。相反，一个单一的凯尼恩细胞群产生高度分支的轴突，提供所有的叶分支。这表明，虽然新翅目蘑菇体的地面平面存在于早期昆虫中，但由独立的凯尼恩细胞亚群组成的模块化亚单位的组织是后来的创新。热蝇的花萼与高度衍生的果蝇Drosophila melanogaster之间的相似性也表明花萼形态与Kenyon细胞数量之间存在相关性。
The mushroom bodies of the insect brain are sensory integration centers best studied for their role in learning and memory. Studies of mushroom body structure and development in neopteran insects have revealed conserved morphogenetic mechanisms. The sequential production of morphologically distinct intrinsic neuron (Kenyon cell) subpopulations by mushroom body neuroblasts and the integration of newborn neurons via a discrete ingrowth tract results in an age-based organization of modular subunits in the primary output neuropil of the mushroom bodies, the lobes. To determine whether these may represent ancestral characteristics, the present account assesses mushroom body organization and development in the basal wingless insect Thermobia domestica. In this insect, a single calyx supplied by the progeny of two neuroblast clusters, and three perpendicularly oriented lobes are readily identifiable. The lobes are subdivided into 15 globular subdivisions (Trauben). Lifelong neurogenesis is observed, with axons of newborn Kenyon cells entering the lobes via an ingrowth core. The Trauben do not appear progressively during development, indicating that they do not represent the ramifications of sequentially produced subpopulations of Kenyon cells. Instead, a single Kenyon cell population produces highly branched axons that supply all lobe subdivisions. This suggests that although the ground plan for neopteran mushroom bodies existed in early insects, the organization of modular subunits composed of separate Kenyon cell subpopulations is a later innovation. Similarities between the calyx of Thermobia and the highly derived fruit fly Drosophila melanogaster also suggest a correlation between calyx morphology and Kenyon cell number.