A team of researchers from the Washington University, and Germany's University Medical Center at Hamburg-Eppendorf and University of Tubingen found that different brain networks ticked at different frequencies.
While some networks activate at 5 hertz, some get active at frequencies between 32 hertz and 45 hertz, the team found. "We found different brain networks ticked at different frequencies, like clocks ticking at different speeds," lead author Joerg Hipp of the University Medical Center was quoted as saying by LiveScience.
Brain studies are commonly done using magnetic resonance imaging, which tracks blood flow, but can't measure frequency. "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, said study co-author Maurizio Corbetta of Washington University.
"We know that some signals in the brain can cycle as high as 500 hertz, or 500 times per second."
In the new study, published in 'Nature Neuroscience', the team analysed brain activities of 43 volunteers with the help of magnetoencephalography (MEG) that can detect minute changes in magnetic fields in the brain which are caused by many cells being active at once.
The researchers found that brain networks that included the hippocampus, an area critical for memory formation, tended to be active at frequencies around 5 hertz. Networks in areas involved in the senses and movement were active between 32 hertz and 45 hertz.
Many other brain networks were found to be active at frequencies between eight and 32 hertz.
The "time-dependent" networks resemble different airline routes, which overlap but each ticks at a different rate, the researchers said.
"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," Corbetta said.
"In the future, this might offer new diagnostic tests or ways to monitor the efficacy of interventions in these debilitating mental conditions," he added.