Cardona A, Saalfeld S, Tomancak P, Hartenstein V
Department of Molecular, Cell, and Developmental Biology, University of California at Los Angeles, Los Angeles, CA 90095, USA.
Cold Spring Harb Symp Quant Biol. 2009;74:235-48. doi: 10.1101/sqb.2009.74.037. Epub 2009 Dec 22.
Neurobiologists address neural structure, development, and function at the level of "macrocircuits" (how different brain compartments are interconnected; what overall pattern of activity they produce) and at the level of "microcircuits" (how connectivity and physiology of individual neurons and their processes within a compartment determine the functional output of this compartment). Work in our lab aims at reconstructing the developing Drosophila brain at both levels. Macrocircuits can be approached conveniently by reconstructing the pattern of brain lineages, which form groups of neurons whose projections form cohesive fascicles interconnecting the compartments of the larval and adult brain. The reconstruction of microcircuits requires serial section electron microscopy, due to the small size of terminal neuronal processes and their synaptic contacts. Because of the amount of labor that traditionally comes with this approach, very little is known about microcircuitry in brains across the animal kingdom. Many of the problems of serial electron microscopy reconstruction are now solvable with digital image recording and specialized software for both image acquisition and postprocessing. In this chapter, we introduce our efforts to reconstruct the small Drosophila larval brain and discuss our results in light of the published data on neuropile ultrastructure in other animal taxa.
神经生物学家在“宏观回路”层面（不同脑区如何相互连接；它们产生何种整体活动模式）以及“微观回路”层面（单个神经元及其在一个脑区内的突起的连接性和生理学如何决定该脑区的功能输出）研究神经结构、发育和功能。我们实验室的工作旨在从这两个层面重建发育中的果蝇大脑。通过重建脑谱系模式可以方便地研究宏观回路，脑谱系形成神经元群，其投射形成连接幼虫和成虫脑区的连贯神经束。由于终末神经元突起及其突触连接的尺寸较小，重建微观回路需要连续切片电子显微镜技术。由于传统上这种方法工作量大，关于动物界大脑微观回路的了解非常少。现在，借助数字图像记录以及用于图像采集和后处理的专门软件，连续电子显微镜重建的许多问题都可以解决。在本章中，我们介绍了重建小型果蝇幼虫大脑的工作，并根据其他动物类群中神经纤维网超微结构的已发表数据讨论了我们的结果。
