The "wires" that carry electrical signals among nerve cells in the brain can influence the threshold at which the cells will send those signals, research on mouse-brain tissue shows.
The finding challenges the conventional view of nerve cells, or neurons. In that scenario, processes within a nerve cell determine whether or not to fire an electrical impulse, and the wire, called an axon, is a passive carrier of that signal.
"[Our research] says that the dogma is incorrect," says lead scientist Raju Metherate of the University of California, Irvine. A more active role for axons could be important for understanding how the brain processes sensory information. It could also have implications for the understanding of neurological diseases such as schizophrenia, Metherate says.
The scientists exposed the axons of isolated mouse neurons to nicotine, which mimics a natural chemical messenger in the brain called acetylcholine. Previous research had shown that axons in seve