Neuronal circuits able to rewire on the fly to shar...( PITTSBURGH Researchers from the Cent...)

PITTSBURGH Researchers from the Center for the Neural Basis of Cognition (CNBC), a joint project of Carnegie Mellon University and the University of Pittsburgh, have for the first time described a mechanism called dynamic connectivity, in which neuronal circuits are rewired on the fly allowing stimuli to be more keenly sensed. The process is described in a paper in the January 2008 issue of Nature Neuroscience, and available online at http://dx.doi.org/10.1038/nn2030.

This new, biologically inspired algorithm for analyzing the brain at work allows scientists to explain why when we notice a scent, the brain can quickly sort through input and determine exactly what that smell is.

If you think of the brain like a computer, then the connections between neurons are like the software that the brain is running. Our work shows that this biological software is changed rapidly as a function of the kind of input that the system receives, said Nathan Urban, associate professor of biological sciences at Carnegie Mellon.

When a stimulus such as an odor is encountered, many neurons start to fire. When many neurons fire at the same time, the signals can be difficult for the brain to interpret. During lateral inhibition, the stimulated neurons send cease-fire messages to the neighboring neurons, reducing the noise and making it easier to precisely identify a stimulus. This process also facilitates accurate recognition of stimuli in many sensory areas of the brain.

In this project, Urban and colleagues specifically examine the process of lateral inhibition in an area of the brain called the olfactory bulb, which is responsible for processing scents. Until now, scientists thought that the connections made by the neurons in the olfactory bulb were dictated by anatomy and could only change slowly.

However, in this current study, Urban and colleagues found that the connections are, in fact, not se
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