AP Biology class blog for discussing current research in Biology

Tag: Sleep Deprivation

Out Like a Light: Sleep Switch in Brain Identified

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

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Lack of Sleep = Excited Brain

Credit: Richard Pagani

Do you get enough sleep during the week? With exams, college applications and numerous extracurricular activities, it is easy to lose track of time and stay up all night working on homework. Personally, I know that I do not get enough sleep every night. However, I did not know that the later people stay awake, the more their brains become active and overly excited.

A recent study has shown that as people stay up late during the night, their nerve cells become more jumpy the longer they are awake. The study consisted of six people staying up all night and having researchers measure their brain responses. The leader of the study, Marcello Massimini of the University of Milan, found that people’s brains become more reactive as hours awake accumulate. To test for signs of altered brain function, the researchers delivered a jolt of magnetic current to the subjects’ skulls. This stimulated an electrical response in the nerve cells. Through electrodes, the scientists measured the strength of this electrical response in the frontal cortex, the region of the brain that is involved in decision-making.

The researchers observed that after a night of sleeplessness, the subjects’ electrical responses were stronger than they were the previous day. The scientists found that this overreaction disappeared after a night’s sleep. Therefore, the study showed that during the hours people are awake, the brain accumulates connections between nerve cells as new things are learned. They think that this excitability in the brain may explain why sleep deprivation can trigger seizures and why hallucinations can accompany an all-nighter because these are events that are usually marked by extreme nerve cell excitation.

Neuroscientist Christopher Colwell of UCLA says that this is “an important finding [because] sleep deprivation is an area of huge interest because most of us do not get enough sleep.” The results from this study help clarify what goes wrong in a brain deprived of sleep. These scientists have also found that the results have a link to depression because it has been found that sleep deprivation can reverse the symptoms of depression. Massimini and his team believe that because the brain is in a boosted state of excitability when it lacks sleep, people who suffer from depression do not exhibit the same symptoms of it when they have not gotten enough sleep. However, this state of excitability is not good for the brain because it needs time to rest and repair itself. Sleep sweeps the brain of extraneous clutter, leaving behind only the most important connections. Therefore, when people are sleep deprived, their brain has so many connections between nerve cells that it does not have the ability to only pick out the most important connections. Thus, this state of excitability is not good for the brain because the brain is never given a break. After learning this, I will definitely try to adjust my sleeping schedule so my brain does not overwork itself!

To learn more about the effects of sleep deprivation on the brain and behavior click on the link below!


Photo Credit: mont3rros4

We all know that sleep deprivation causes the brain to become exhausted, but  a recent new study has shown that sleep deprivation causes nerve cells to become increasingly jumpy.


Most of us these days don’t get enough sleep. But sleep deprivation can cause people to have seizures and hallucinations. People believe that sleep deprivation lowers a person’s alertness, but Marcello Massimini from the University of Milan and his fellow colleagues have discovered that the brain actually becomes more reactive as hours awake accumulate.

Six people were gathered and did not sleep for a whole day. Massimini gave each person a jolt of magnetic current to the participants skull. The nerve cell received an electrical response and Massimini was able to measure the strength of the electrical response. He did this to the patients twice. Once right after they woke up from sleep and once after they hadn’t sleep for a whole day. The results were that the patients had a stronger electrical response after they hadn’t slept for a whole day than when they just woke up.

The theory is that the brain accumulates connection as the person learns new things. Sleep clears the brain of extra information and leaves only the most important information and connections. These enhanced excitability could be the explanation of why people have seizures after they haven’t slept in a whole day. Also doctors have induced seizures on patients by keeping them up all night. New studies are being tested if wether sleep deprivation can lead to reversing depression since the brain has a heightened excitement without sleep.

Other effects of sleep deprivation are stress, memory impairment, and poor quality of life. It is advisable for teenagers and adults to get about 8-9 hours of sleep. Now lets get some sleep!

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