Althaus Vanessa, Jahn Stefanie, Massah Azar, Stengl Monika, Homberg Uwe
Department of Biology, Animal Physiology, Philipps-University of Marburg, Marburg, Germany.
Faculty of Mathematics and Natural Sciences, Institute of Biology, Animal Physiology, University of Kassel, Kassel, Germany.
J Comp Neurol. 2022 Dec;530(18):3126-3156. doi: 10.1002/cne.25396. Epub 2022 Aug 29.
The Madeira cockroach Rhyparobia maderae is a nocturnal insect and a prominent model organism for the study of circadian rhythms. Its master circadian clock, controlling circadian locomotor activity and sleep-wake cycles, is located in the accessory medulla of the optic lobe. For a better understanding of brain regions controlled by the circadian clock and brain organization of this insect in general, we created a three-dimensional (3D) reconstruction of all neuropils of the cerebral ganglia based on anti-synapsin and anti-γ-aminobutyric acid immunolabeling of whole mount brains. Forty-nine major neuropils were identified and three-dimensionally reconstructed. Single-cell dye fills complement the data and provide evidence for distinct subdivisions of certain brain areas. Most neuropils defined in the fruit fly Drosophila melanogaster could be distinguished in the cockroach as well. However, some neuropils identified in the fruit fly do not exist as distinct entities in the cockroach while others are lacking in the fruit fly. In addition to neuropils, major fiber systems, tracts, and commissures were reconstructed and served as important landmarks separating brain areas. Being a nocturnal insect, R. maderae is an important new species to the growing collection of 3D insect brain atlases and only the second hemimetabolous insect, for which a detailed 3D brain atlas is available. This atlas will be highly valuable for an evolutionary comparison of insect brain organization and will greatly facilitate addressing brain areas that are supervised by the circadian clock.
马德拉蜚蠊（Rhyparobia maderae）是一种夜行性昆虫，也是研究昼夜节律的重要模式生物。其主昼夜节律时钟控制着昼夜运动活动和睡眠-觉醒周期，位于视叶的副髓质中。为了更好地了解受昼夜节律时钟控制的脑区以及该昆虫的整体脑组织结构，我们基于全脑的抗突触素和抗γ-氨基丁酸免疫标记，创建了脑神经节所有神经纤维网的三维（3D）重建。确定了49个主要神经纤维网并进行了三维重建。单细胞染料填充补充了数据，并为某些脑区的不同细分提供了证据。在果蝇（Drosophila melanogaster）中定义的大多数神经纤维网在蜚蠊中也能区分出来。然而，在果蝇中确定的一些神经纤维网在蜚蠊中并非作为独立的实体存在，而另一些在果蝇中则不存在。除了神经纤维网，主要的纤维系统、束和连合也进行了重建，并作为分隔脑区的重要标志。作为一种夜行性昆虫，马德拉蜚蠊是不断增加的3D昆虫脑图谱收藏中的一个重要新物种，也是第二个有详细3D脑图谱的不完全变态昆虫。该图谱对于昆虫脑组织结构的进化比较将具有很高的价值，并将极大地有助于研究受昼夜节律时钟监督的脑区。
