Scientists said brain cells generate and propagate nerve impulses by controlling the flow of sodium and potassium ions -- an action requiring energy. The amount of energy was previously estimated using a giant nerve cell from a squid.
But now a study by researchers at the Max Planck Institute for Brain Research in Frankfurt, Germany, shows squid cell studies overestimated the amount of energy necessary to generate an action potential by nearly a factor of four. That, said the researchers, suggests human brains also have the same potential to be energy efficient.
The study, published in the journal Science, was reviewed by F1000 Biology members Venkatesh Murthy, a professor of molecular and cellular biology at Harvard University, and Jakob Sorensen, a professor of neuroscience at the University of Copenhagen in Denmark.
Murthy said the researchers recorded the voltage generated by nerve cells to "show that a rather subtle separation between the timing of sodium entry and potassium exit during action potentials can determine how much energy is expended to maintain the ionic gradients."
Murthy said the results are important, not just for a basic understanding of brain metabolism, but also for interpreting signals detected by non-invasive
brain imaging techniques."
Added Sorensen, "The amazing thing is that we didn't realize the result a long time ago."
Copyright 2009 by United Press International.