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The economy of brain network organisation
The brain is expensive, incurring high material and metabolic costs for its size — relative to the size of the body — and many aspects of brain network organization can be mostly explained by a parsimonious drive to minimize these costs. However, brain networks or connectomes also have high topological efficiency, robustness, modularity and a 'rich club' of connector hubs. Many of these and other advantageous topological properties will probably entail a wiring-cost premium. In a recent review in Nature Reviews Neuroscience, Cambridge Neuroscientist Professor Ed Bullmore (pictured right, BCNI and Department of Psychiatry) and his collaborator Olaf Spoons (Indiana University) propose that brain network organization is the result of an economical trade-off between the physical cost of the network and the adaptive value of its topology. This process of negotiating, and re-negotiating, trade-offs between wiring cost and topological value continues over long (decades) and short (millisecond) timescales as brain networks evolve, grow and adapt to changing cognitive demands. The cognitive, emotional, perceptual and motor symptoms of chronic brain disorders represent a disruption of normal cognitive or behavioural functions of the brain. These ‘higher-order’ functions are normally associated with synchronized activations of several distributed brain regions and there is strong evidence from neuroimaging studies for abnormal connectivity and network phenotypes in many neurological and psychiatric disorders. In this review, Bullmore provides an economical analysis of neuropsychiatric disorders, and highlights the vulnerability of the more costly elements of brain networks to pathological attack or abnormal development.
In a recent publication in Proceedings of the National Academy of Sciences (PNAS), Bullmore and colleagues described how they developed a simple mathematical model of the brain, which provides a remarkably complete statistical account of the complex web of connections between various brain regions. To watch a video which shows the pattern of connections that make up a network in the brain, please visit:
Posted on 24/04/2012
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