According to a study published May 6 in Nature Neuroscience, researchers at Washington University School of Medicine in St. Louis, the University Medical Center at Hamburg-Eppendorf and the University of Tübingen have found that networks in the brain may avoid congestion at their busiest intersections by communicating on different frequencies.

Co-author Maurizio Corbetta, M.D., the Norman J. Stupp Professor of Neurology at Washington University, explained:

“Many neurological and psychiatric conditions are likely to involve problems with signaling in brain networks. Examining the temporal structure of brain activity from this perspective may be especially helpful in understanding psychiatric conditions like depression and schizophrenia, where structural markers are scarce.”

Researchers generally use magnetic resonance imaging (MRI), which tracks blood flow, to examine brain networks. They believe that an increase in blood flow to part of the brain suggests increased brain cell activity.

Corbetta said:

“Magnetic resonance imaging is a useful tool, but it does have limitations. It only allows us to track brain cell activity indirectly, and it is unable to track activity that occurs at frequencies greater than 0.1 hertz, or once every 10 seconds. We know that some signals in the brain can cycle as high as 500 hertz, or 500 times per second.”

In this study, the researchers examined brain activity in 43 healthy volunteers using a technique called magnetoencephalography (MEG). MEG maps brain activity by recording magnetic fields produced by electrical currents in the brain. MEG can detect signals up to 100 hertz.

Lead author of the study, Joerg Hipp, Ph.D., of the University Medical Center at Hamburg-Eppendorf and the University of Tübingen, both in Germany, said:

“We found that different brain networks ticked at different frequencies, like clocks ticking at different speeds.”

For instance, networks in the hippocampus region of the brain seemed to be active at frequencies around 5 hertz; networks in areas of the brain associated with movement and senses were active at frequencies around 32 an 45 hertz; and several other brain networks were active between 8 and 32 hertz. According to the researchers, these networks are similar to different airline route maps, overlapping but each ticking at a different rate.

Corbetta explained:

“There have been a number of fMRI studies of depression and schizophrenia showing ‘spatial’ changes in the organization of brain networks. MEG studies provide a window into a much richer ‘temporal’ structure. In the future, this might offer new diagnostic tests or ways to monitor the efficacy of interventions in these debilitating mental conditions.”

Written By Grace Rattue