A new study reveals that the suprachiasmatic nucleus (SCN) is driven, in part, by metabolism, the production and flow of chemical energy in cells. In order to draw this conclusion, researchers focused primarily on a phenomenon known as "redox" in tissues of the SCN from the brains of rats and mice.
Redox represents the energy changes of cellular metabolism (usually through the transfer of electrons). When a molecule gains one or more electrons, scientists call it a reduction; when it loses electrons, they say it is oxidized. These redox reactions, the researchers found, oscillate on a 24-hour cycle in the brain clock, and literally open and close channels of communication in brain cells.
"The language of the brain is electrical; it determines what kind of signals one part of the brain sends to the other cells in its tissue, as well as the other parts of the brain nearby," said University of Illinois cell and developmental biology professor Martha Gillette, who led the study. "The fundamental discovery here is that there is an intrinsic oscillation in metabolism in the clock region of the brain that takes place without external intervention. And this change in metabolism determines the excitable state of that part of the brain."
The new findings, reported in the journal Science, alter basic assumptions about how the brain works, Gillette said.
"Basically, the idea has always been that metabolism is serving brain function. What we’re showing is metabolism is part of brain function," she said. "Our study implies that changes in cellular metabolic state could be a cause, rather than a result, of neuronal activity."