Dhawale Ashesh, Bhalla Upinder S
National Centre for Biological Sciences, Tata Institute of Fundamental Research (TIFR), Bellary Road, Bangalore, India 560065.
HFSP J. 2008 Feb;2(1):12-6. doi: 10.2976/1.2835214. Epub 2008 Jan 30.
A century ago, Ramón y Cajal proposed that the brain consisted of huge numbers of neurons that communicated with each other through junctions called synapses. Today we routinely monitor single neuron and single synapse responses, and we have elaborate maps of connections between different regions of the brain. What we lack is a way to bridge these two scales of representing neuronal circuits. The challenges in doing so are formidable: even a small mammalian neuronal circuit has many thousands of neurons and millions of synapses. Can we keep track of individual cells and synapses in this crowd? Here we examine how two recent techniques may complement each other to do so. The recent "Brainbow" method is a way to color-code cells and their projections, so we can see which cells come near each other, but cannot be sure they connect. Functional circuit mapping tells us about connections between cells, but we cannot identify more than a handful at a time. Together these methods may fill in each other's blanks and give us brain wiring diagrams that combine scale and precision.
一个世纪前，拉蒙·卡哈尔提出大脑由大量神经元组成，这些神经元通过称为突触的连接相互通信。如今，我们经常监测单个神经元和单个突触的反应，并且已经绘制了大脑不同区域之间连接的详尽图谱。我们所缺乏的是一种在这两种表示神经元回路的尺度之间架起桥梁的方法。这样做面临的挑战是巨大的：即使是一个小型哺乳动物神经元回路也有成千上万个神经元和数百万个突触。我们能在这众多细胞和突触中追踪单个细胞和突触吗？在这里，我们研究最近的两种技术如何相互补充以做到这一点。最近的“脑彩虹”方法是一种对细胞及其投射进行颜色编码的方法，这样我们就能看到哪些细胞彼此靠近，但无法确定它们是否连接。功能回路图谱能告诉我们细胞之间的连接情况，但我们一次只能识别少数几个。这些方法结合起来可能会相互补充，为我们提供兼具尺度和精度的大脑布线图。
