William Atkins
Friday, 24 April 2009 19:48
Science -
Biology
Page 1 of 3
A Belgium study involving sleep and circadian rhythm found the brain is continually trying to balance the circadian signal (when you want to naturally sleep and be awake) and homeostatic pressure (the counting of the number of hours during sleep and while awake). This battle determines if you are more attentive during the afternoons and evenings.
The researchers—led by Christina Schmidt (of the Cyclotron Research Centre and the Cognitive and Behavioral Neuroscience Centre, both at the University of Liège, Belgium; and Philippe Peigneux of the Cyclotron Research Centre and the Neuropsychology and Functional Neuroimaging Research Unit at the Université Libre de Bruxelles, Brussels, Belgium—looked at the circadian clock and the sleep homeostat.
The
circadian clock regulates the body’s cycle of sleeping and waking by sensing light or darkness, specifically helping to control blood pressure and body temperature; for example, it lowers body temperature during sleeping hours.
The master circadian clock is hardwired in the brain, and basically tells your body when you like to get up in the morning--early, late, or in-between.
The
sleep homeostat is a clock-like regulator that senses the amount of time a person has been awake or asleep; for example, when a person has been awake for a long time, it tells the body it is tired and it is time for sleep.
The sleep homeostat basically keeps track of how long you have been asleep or awake and tells you that after so many hours it is time to wake up or to go to sleep.
The article written by these researchers (“
Homeostatic Sleep Pressure and Responses to Sustained Attention in the Suprachiasmatic Area”) appeared in the journal
Science on April 24, 2009.
The researchers state in their paper,
“Throughout the day, cognitive performance is under the combined influence of circadian processes and homeostatic sleep pressure. Some people perform best in the morning, whereas others are more alert in the evening. These chronotypes provide a unique way to study the effects of sleep-wake regulation on the cerebral mechanisms supporting cognition.”
They use the word “chronotypes” to describe groups of people with different sleep-and-wake cycles.
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