Theory About Biological Clock Changed
Excerpts:
University of Michigan mathematicians and their British colleagues say they have identified the signal that the brain sends to the rest of the body to control biological rhythms, a finding that overturns a long-held theory about our internal clock.
Imagine a metronome in the brain that ticks quickly throughout the day, then slows its pace at night. The rest of the body hears the ticking and adjusts its daily rhythms, also known as circadian rhythms, accordingly.
The researchers found that during the day, SCN cells expressing per1 sustain an electrically excited state but do not fire. They fire for a brief period around dusk, then remain quiet throughout the night before releasing another burst of activity around dawn. This firing pattern is the signal, or code, the brain sends to the rest of the body so it can keep time.
"The old theory was that the cells in the SCN which contain the clock are firing fast during the day but slow at night. But now we've shown that the cells that actually contain the clock mechanism are silent during the day, when everybody thought they were firing fast," Diekman said.
Piggins said the findings "force us to completely reassess what we thought we knew about electrical activity in the brain's circadian clock." In addition, the results demonstrate the importance of interdisciplinary collaborative research, he said.
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