sleep switch – BioQuakes

Researchers from Oxford University’s Center of Neural Circuits and Behavior have identified the switch in the brain, which causes sleep, from a study of fruit flies. This switch regulates sleep promoting neurons in the brain. When one is tired and in need of sleep, these neurons will activate. Once you are fully rested, neuron activity will die down. Though this new insight was gained through studying fruit flies, or Drosophila, the researchers believe this information is also relevant to humans. In the human brain, there are similar neurons that are active during sleep and are the targets of general anesthetics that cause sleep. These facts support the idea that humans have a sleep mechanism like that found in fruit flies, according to Dr. Jeffrey Donlea, one of the lead authors of the study. The findings of this study were published in the journal, Neuron.The discovery of this sleep switch is important for a number of reasons like finding new treatments for sleep disorders, but it is just a small piece of the enigma that is sleep. The internal signal, which this sleep switch responds to, is still unknown, as is the activity of these sleep-promoting cells while we are awake. We do not even know why humans and all other animals need sleep.

In spite of these mysterious, scientists do know how the body regulates sleep. Humans and animals have a body clock, which makes us accustomed to the 24 hour cycle of day and night, and a sleep switch, which logs the hours you are awake and causes you to sleep when you need rest. When this mechanism is off or not being used, sleep deficiency increases. The combination of these two is the most likely cause of us sleeping at night.

The significance of this switch in the process of sleep and its relationship to bodily function was found when studying the fruit flies. If they did not sleep, mutant flies cannot regain these lost sleep hours. Sleep-deprived flies are also more likely to nod off and be cognitively impaired. Like sleep-deprived humans, these flies were subject to severe learning and memory deficiencies. In the mutant flies, the researchers proved the insomnia of the flies was due to a broken part of the electrical activity switch, which caused the sleep-inducing neurons to always be off.

Why do you think sleep is important? How is this discovery significant and how do you think this information will be used in the future? Will the mystery of sleep be solved soon?

Photograph by Pedro Ribeiro Simões

Other helpful links:

http://www.sciencedaily.com/releases/2014/02/140219124730.htm
http://www.ninds.nih.gov/disorders/brain_basics/understanding_sleep.htm
http://www.sleepfoundation.org

Photo taken by André Karwath
http://en.wikipedia.org/wiki/File:Drosophila_melanogaster_-_front_(aka).jpg

Scientists at Oxford University’s Centre for Neural Circuits and Behaviour “identified the switch in the brain that sends us off to sleep” (see original article) by doing a study on fruit flies (Drosophilia). This part of the brain had been discovered in 2011 (see this article about the discovery), but the new research identifies more specifically the molecules and sleep-causing cells involved.

The switch (which is made of several molecules) in the fly brain is likely similar to the switch in the human brain because both species have a similar group of sleep neurons. This switch regulates the neurons that cause organisms to sleep (the neurons that are targets of anesthetics). The sleep neurons are active when the organism is tired and needs sleep (it is the result of these neurons being activated that causes sleep), and less active when it is well rested. The switch or “homeostat” is one of two devices that regulate sleep (the other is the body clock that distinguishes night from day in humans). It records the hours a person is awake and then signals the neurons that cause sleep when the person needs to rest.

In the study, flies were kept awake all night. Regular flies slept more the next day, while the mutants could not do this. The mutants were found to “nod off” (determined by the fact that flies stop moving when they sleep) and were found to have learning and memory issues. In these mutants, researchers found a key molecular piece of the “sleep switch” and determined that it was broken. This resulted in the neurons that cause sleep not being activated; this led to insomnia.

Now that the sleep switch has been “pinpointed”, what new drugs will be created to treat insomnia and other sleep disorders? People are also wondering if this more specific discovery will help answer the larger question of why animals need sleep at all. As someone who does not get much sleep, I find this new identification very interesting and relevant in the busy lives of people today.

BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: sleep switch

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