The network properties underlying the circuit operations of the brain are still basically unknown. There is no complex brain in which the overall activity patterns have been observed in real time. This project will chart the major patterns of information flow in a small, complex brain, and analyze its functional network architecture. Treating the network in a totally unbiased way, it will generate data from artificial stimulation of brain circuits aimed at surveying the paths of information flow, without regard to why the brain is doing anything or what the output is. The task will be carried out in an unusual collaboration between experimental and computational neuroscientists and network theorists to chart information flow through the complex, but relatively small, brain of the fruit fly Drosophila and then to analyze the principles of network function that it reveals. The rationale for focusing on the fruit fly brain is that it is small enough to be possible to monitor its activity completely, but also complex enough (150,000 nerve cells) to offer solutions to the major problems of complex brain networks. In addition, the entire wiring pattern of its nerve cell connections is well under way and will soon be completed. The goal of this project is to characterize the network from the perspective of its underlying function and architecture, which not may not be identical with its actual physical layout. With the data in hand, a search will be conducted for the engineering the design principles embodied in the brain's networks. From these findings, a general theory of information flow in the brain will be formulated, based on the first broad-based, whole network analysis.
Intellectual Merit: The project aims at mining biological systems for principles and strategies that can be applied to problems in computing and engineering. At the same time, it tackles a major problem in neuroscience in a technically feasible fashion. The challenge to understanding the overall strategy used by the brain is the fact that, in its operations, the whole is greater than the sum of the parts. This feature, known as an "emergent" property, arises from the timing and patterns of signaling activity of many thousands of nerve cells. If one had access to that data, and could correlate the activity with the pattern of nerve cell connections brain, it would be possible to formulate a theoretical basis for large-scale neuronal coding. Understanding this process, in turn, holds substantial promise for applications in computing and engineering.
Broader Impact: Educational Impact: In addition to providing the opportunity for training of graduate students, postdoctoral fellows, and undergraduates, a knowledge of the fundamental strategies of information processing in the brain would allow us to design educational strategies that take maximum advantage of that understanding.
Technological Impact: The principles and theoretical formulation that will emerge from this project also have the potential for providing novel strategies for computer network design and traffic flow of signals, and for engineering strategies that involve networks and information flow. The experiments outlined for this project constitute a new approach to the question of whether there are fundamental underlying principles of brain network operation which, if discerned, would have wide-ranging implications for applications such as the design and implementation of artificial networks constructed for computing, engineered devices, and communications. In addition, properties such as adaptability, versatility, and robustness are keenly sought in these areas, and efforts are aimed at being able to capture the ability of gene networks to carry them out.
