Thomas R. Insel, Nora D. Volkow, Ting-Kai Li, James F. Battey, Story C. Landis, Neuroscience Networks: Data-sharing in an Information Age, PLoS Biol 1(1): e7 (Essay, October 13, 2003)(© 2003 Public Library of Science. This is an open-access article distributed under the terms of the Public Library of Science Open-Access License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.):
In parallel to the worldwide effort to map the human genome, investigators in neuroscience have used a range of techniques to map the brain. The efforts share some superficial similarities: the genome has 3 × [10 to the 9th power] bases and the human brain has roughly 100 × [10 to the 9th power] neurons; both the genome and the brain have embedded modules of functional units (genes versus circuits) that can be mapped in space; and localization of both genes and circuits requires computational power that can be distributed across laboratories. But the analogy breaks down quickly. Whereas fundamental genome data can be addressed as unidimensional text of four letters in varying order, a comprehensive map of the brain includes molecular, cellular, system, and behavioral data—all of which are dynamic, interacting, and interdependent. For example, brain circuitry is organized in three-dimensional space constantly changing in time, with each neuron having [10 to the 3rd power] – [10 to the 4th power] synapses and with many of those synapses capable of plasticity that may, in turn, have significant functional consequences.