Our body is regulated by an invisible clock that influences our wakefulness, sleep, thoughts, and emotions. The circadian clock is an important regulatory feature, yet neuroscientists still don’t completely understand it. Although cognitive tests can be performed, it was difficult to monitor brain cells over the course of a day until neuroscientist and Dana Alliance member Huda Akil, M.D., designed an experiment that gave a new perspective on circadian clocks.
“Maybe it’s simple-minded, but nobody had thought of it,” she said to The New York Times in a recent article. Her team examined the healthy brains of 55 donors who had died suddenly at different times of the day. As reported by the Times:
As each person died, his brain cells were in the midst of making proteins from certain genes. Because the brains had been quickly preserved, the scientists could still measure the activity of those genes at the time of death.
Most of the genes they examined didn’t show any regular pattern of activity over the course of the day. But they found that more than 1,000 genes followed a daily cycle. People who died at the same time of day were making those genes at the same levels.
The findings were so consistent that they even enabled the scientists to determine the time of death within the hour.
Knowing that this consistency existed led Akil to look at deviations from the pattern. She examined brains from other donors who had suffered severe depression and found they did not have the same patterns as the brains in the previous experiment. Akil knew that, “sleep and activity cycles are a very big part of psychiatric illnesses,” and this experiment illustrated that idea.
Colleen A. McClung, Ph.D., a researcher at the University of Pittsburgh School of Medicine replicated Akil’s experiment, and also investigated an additional question: Is there a difference between old and young brains? McClung found that circadian rhythms in the brain seem to deteriorate over time and the reason could be that older adults stop producing the proteins needed to maintain them. Other genes become active only in older age, which McClung believes is the brain trying to compensate for the deterioration.
These experiments have brought a new understanding to a system that is important in regulating some of our most important functions. They can teach us a lot about psychiatric illnesses and may give us insight into how to treat them.