I woke up on 01 Nov 09, Sunday and was surprised to see the time in my alarm clock. I looked at my cell phone and realized that the alarm clock was one hour ahead. I suddenly realized that day light saving has begun. Though, I slept more than I normally do, but there was some relief after watching time in my cell phone. I turned my alarmed clock one hour back and was wondering if it would have been that much easier to adjust my internal biological clock in a similar way. This would come handy when I am travelling back and forth between countries and would not be affected by jet lag. We may not be there yet, but researchers at University of Michigan mathematicians and their British colleagues have made discoveries to understand our internal clock.
The researchers took the help of mathematical model to analyze the electrical patterns and found the old theory of mechanism of internal clock as wrong and proposed a new theory. Let us take a look, what part of brain is responsible for internal biological clock and what are the old and new theories.
What is the old theory?
The finding by University of Michigan mathematicians and their British colleagues overturns a long-held theory about our internal clock. The SCN, pine cone shaped and the size of a grain of rice, interacts with many other regions of the brain. It controls the internal clock by mechanism called circadian rhythms.
What is the old theory of internal clock or circadian rhythms?
SCN cells fire electrical pulses, which are believed to control the internal clock of body. According to the most popular theory, until now, SCN cells fire electrical signals at...
faster speed at the day time and slow down at night.
What is the new theory of internal clock mechanism?
As per the researchers the SCN are comprised of two types of cells; namely clock cells (which express a gene call per1) and non-clock cells. Researchers were able to clock cells from non-clock cells and measure the signals from the clock cells.
The observations from the clock cells revealed that SCN cells expressing per1 sustain an electrically excited state but do not fire. These cells fire for a short time during dusk and then remain silent throughout the night before releasing another burst of activity around dawn. Researchers further acknowledged that this firing pattern is signal or code that is send to rest of the body from the brain to keep time.
How was this new theory established?
Researchers created mathematical model and collected firing patterns for more than 400 mouse SCN cells. Researchers then plugged the experimental results into their model and found a close match between the model and experimental results. Though the experiments were done on mouse, it is believed that same mechanisms prevail in humans.
University of Michigan mathematician Daniel Forger said that “this is a perfect example of how a mathematical model can make predictions that are completely at odds with the prevailing views yet, upon further experimentation, turn out to be dead-on.”
What would be benefit of this new theory on internal clock?
Dr. Forger said that the increased of understanding of the human biological clock is crucial to solve sleep problems like insomnia and jet lag. He added that “New insights about the body’s central pacemaker might also, someday, advance efforts to treat diseases influenced by the internal clock, including cancer, Alzheimer’s disease and mood disorders.”