Neurons are often considered to be the primary computational units of the brain. But it was unclear whether the connections between neurons actively participated in the computational process, or merely acted to convey information.
"Our study shows that synapses not only ensure the flow of information but actively modify their properties to help with computations," says Howard Hughes Medical Investigator Charles Stevens, a professor in the Molecular Neurobiology Laboratory and senior author of the study.
Lead author Vitaly Klyachko, a post-doctoral researcher working with Stevens explains, "Brain cells produce a lot of background chatter. Synapses filter this random noise and enhance relevant information. They work as very fine-tuned filters that do exactly what you would want them to do."
Brain cells signal by sending electrical impulses along axons, long, hair-like extensions that reach out to neighboring nerve cells. They make contact via synapses, from the Greek word meaning "to clasp together." When an electrical signal reaches the end of an axon, the voltage change triggers release of neurotransmitters, the brain's chemical messengers. These neurotransmitter molecules then travel across the space between neurons at a synapse and trigger an electrical signal in the adjacent cell.
Scientists had postulated that synapses play a major role in information processing in the brain. But not all signals are transmitted. Just like cell phone calls are dropped in areas of spotty coverage, synapses drop up to 90 percent of all incoming signals. "The unrelia
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Contact: Gina Kirchweger
kirchweger@salk.edu
858-453-4100 x1340
Salk Institute
12-Jun-2006