Posts tagged sleep
Articles and news from the latest research reports.
Forget All-Night Studying, a Good Night’s Sleep Is Key to Doing Well on Exams
As fall semesters wind down at the country’s colleges and universities, students will be pulling all-night study sessions to prepare for final exams. Ironically, the loss of sleep during these all-nighters could actually work against them performing well, says a Harris Health System sleep specialist.
Dr. Philip Alapat, medical director, Harris Health Sleep Disorders Center, and assistant professor, Baylor College of Medicine, recommends students instead study throughout the semester, set up study sessions in the evening (the optimal time of alertness and concentration) and get at least 8 hours of sleep the night before exams.
“Memory recall and ability to maintain concentration are much improved when an individual is rested,” he says. “By preparing early and being able to better recall what you have studied, your ability to perform well on exams is increased.”
Alapat’s recommendations:
• Get 8-9 hours of sleep nightly (especially before final exams)• Try to study during periods of optimal brain function (usually around 6-8 p.m.)
• Avoid studying in early afternoons, usually the time of least alertness
• Don’t overuse caffeinated drinks (caffeine remains in one’s system for 6-8 hours)
• Recognize that chronic sleep deprivation may contribute to development of long-term diseases like diabetes, high blood pressure and heart disease
If suffering from bouts of chronic sleep deprivation or nightly insomnia that lasts for more than a few weeks, Alapat suggests consulting a sleep specialist.
Today saw the launch of Re-Timer, a wearable green light device invented by Flinders University sleep researchers to reset the body’s internal clock.
The portable device, which is worn like a pair of sunglasses and emits a soft green light onto the eyes, will help to counter jet lag, keep shift workers more alert and get teenagers out of bed by advancing or delaying sleeping patterns.
Psychologist Professor Leon Lack, the device’s chief inventor, said that the light from Re-Timer stimulates the part of the brain responsible for regulating the 24-hour body clock.
The device has been designed with the benefit of 25 years of sleep research at Flinders University.
“Body clocks or circadian rhythms influence the timing of all our sleeping and waking patterns, alertness, performance levels and metabolism,” Professor Lack said.
“Photoreceptors in our eyes detect sunlight, signal our brain to be awake and alert, and set our rhythms accordingly. These rhythms vary regularly over a 24-hour cycle. However, this process is often impaired by staying indoors, traveling to other times zones, working irregular hours, or a lack of sunlight during winter months.
“Our extensive research studies have shown that green light is one of the most effective wavelengths for advancing or delaying the body clock, and to date is the only wearable device using green light.”
Professor Lack recommended wearing the glasses for three days for 50 minutes each day either after awakening in the morning to advance the body clock, or before bed for those wanting to delay the body clock to wake up later.
He said that Re-Timer’s light therapy offers a safer and, in many cases, more effective treatment for mistimed sleep than drug alternatives.
The device is being produced by local manufacturing firm SMR Components.
Researchers at Emory University School of Medicine have discovered that dozens of adults with an elevated need for sleep have a substance in their cerebrospinal fluid that acts like a sleeping pill.
The results are scheduled for publication online Wednesday by the journal Science Translational Medicine.
Some members of this patient population appear to have a distinct, disabling sleep disorder called “primary hypersomnia,” which is separate from better-known conditions such as sleep apnea or narcolepsy. They regularly sleep more than 70 hours per week and have difficulties awakening. When awake, they still have reaction times comparable to someone who has been awake all night. Their sleepiness often interferes with work or school attendance, and conventional treatments such as stimulants bring little relief.
"These individuals report feeling as if they’re walking around in a fog — physically, but not mentally awake," says lead author David Rye, professor of neurology at Emory University School of Medicine and director of research for Emory Healthcare’s Program in Sleep. "When encountering excessive sleepiness in a patient, we typically think it’s caused by an impairment in the brain’s wake systems and treat it with stimulant medications. However, in these patients, the situation is more akin to attempting to drive a car with the parking brake engaged. Our thinking needs to shift from pushing the accelerator harder, to releasing the brake."
In a clinical study with seven patients who remained sleepy despite above-ordinary sleep amounts and treatment with stimulants, Emory researchers showed that treatment with the drug flumazenil can restore alertness, although flumazenil’s effectiveness was not uniform for all seven. Alertness was gauged through the psychomotor vigilance test, a measurement of reaction time.
Could poor sleep contribute to symptoms of schizophrenia?
Neuroscientists studying the link between poor sleep and schizophrenia have found that irregular sleep patterns and desynchronised brain activity during sleep could trigger some of the disease’s symptoms. The findings, published in the journal Neuron, suggest that these prolonged disturbances might be a cause and not just a consequence of the disorder’s debilitating effects.
The possible link between poor sleep and schizophrenia prompted the research team, led by scientists from the University of Bristol, the Lilly Centre for Cognitive Neuroscience and funded by the Medical Research Council (MRC), to explore the impact of irregular sleep patterns on the brain by recording electrical brain activity in multiple brain regions during sleep.
For many people, sleep deprivation can affect mood, concentration and stress levels. In extreme cases, prolonged sleep deprivation can induce hallucinations, memory loss and confusion all of which are also symptoms associated with schizophrenia.
Dr Ullrich Bartsch, one of the study’s researchers, said: “Sleep disturbances are well-documented in the disease, though often regarded as side effects and poorly understood in terms of their potential to actually trigger its symptoms.”
Using a rat model of the disease, the team’s recordings showed desynchronisation of the waves of activity which normally travel from the front to the back of the brain during deep sleep. In particular the information flow between the hippocampus — involved in memory formation, and the frontal cortex — involved in decision-making, appeared to be disrupted. The team’s findings reported distinct irregular sleep patterns very similar to those observed in schizophrenia patients.
Dr Matt Jones, the lead researcher from the University’s School of Physiology and Pharmacology, added: “Decoupling of brain regions involved in memory formation and decision-making during wakefulness are already implicated in schizophrenia, but decoupling during sleep provides a new mechanistic explanation for the cognitive deficits observed in both the animal model and patients: sleep disturbances might be a cause, not just a consequence of schizophrenia. In fact, abnormal sleep patterns may trigger abnormal brain activity in a range of conditions.”
Cognitive deficits — reduced short term memory and attention span, are typically resistant to medication in patients. The findings from this study provide new angles for neurocognitive therapy in schizophrenia and related psychiatric diseases.
(Source: eurekalert.org)
Magnetic brain stimulation treats depression independent of sleep effect
While powerful magnetic stimulation of the frontal lobe of the brain can alleviate symptoms of depression, those receiving the treatment did not report effects on sleep or arousal commonly seen with antidepressant medications, researchers say.
“People’s sleep gets better as their depression improves, but the treatment doesn’t itself cause sedation or insomnia.” said Dr. Peter B. Rosenquist, Vice Chair of the Department of Psychiatry and Health Behavior at the Medical College of Georgia at Georgia Health Sciences University.
The finding resulted from a secondary analysis of a study of 301 patients at 23 sites comparing the anti-depressive effects of the Neuronetics Transcranial Magnetic Stimulation Therapy System to sham (placebo) treatment in patients resistant to antidepressant medications. TMS sessions were given for 40 minutes, five days a week for six weeks. Initial findings, published in the journal Biological Psychiatry in 2007, were the primary evidence in the Food and Drug Administration’s approval of TMS for depression. The secondary review reaffirmed TMS’s effectiveness in depression but revealed no differences in rates of insomnia or sleepiness among those who got actual and sham (placebo) therapy. Patients in the treatment group were also no more likely to request medication for insomnia or anxiety.
“It’s important for us to understand the full range of the effects of any treatment we give,” said Rosenquist, corresponding author of the study in the journal Psychiatric Research. The new findings will assuage worries of sleep-related side effects and remind physicians to remain alert to residual insomnia in depressed patients they are treating with TMS, the researchers report.
Sleep problems are a common side effect of major antidepressants: some drugs sedate patients while others stimulate them and increase insomnia. Insomnia occurs in 50-90 percent of patients with major depressive disorder. Other depressed patients complain they sleep too much. The good news is that TMS does not contribute to insomnia or oversleeping.
“One of the many bad things about depression is that often patients cannot sleep. We think it’s a significant symptom,” Rosenquist said. “If patients can’t sleep, it really adds to their distress, and even increases the likelihood of suicide. We need antidepressant treatments that patients can tolerate so that they will stay with the treatment, which takes weeks to fully achieve. Our study adds to the evidence showing that TMS has remarkably few side effects.” Patients often seek TMS as an option or adjunct to medication to avoid medication side effects.
“Mood disorders are associated with widespread structural and functional changes in the human brain, which can be reversed with successful treatment,” Rosenquist said. “Clinical researchers are working to find the optimal way to restore normal brain function.”
TMS targets the prefrontal cortex of the brain, involved in mood regulation as well as other higher-order functions like planning, evaluating and decision-making. In this procedure, patients sit in a recliner and receive brief pulses of a MRI strength magnet held against the front of the head. The magnetic energy of TMS causes the brain cells closest to the surface of the brain to increase their activity which in turn influences the activity of the brain as a whole.
Major Depressive Disorder affects approximately 14.8 million, or about 6.7 percent of American adults in a given year, according to the National Institute of Mental Health. It’s the leading cause of disability in ages 15 to 44. Despite the numbers, Rosenquist concedes that it’s not clear what causes depression or exactly how antidepressants and other therapies, such as TMS, work. “It’s an important puzzle and the work continues. We are excited to be a part of this effort at Georgia Health Sciences University.”
(Source: news.georgiahealth.edu)
Same neurons at work in sleep and under anesthesia
Anesthesiologists aren’t totally lying when they say they’re going to put you to sleep. Some anesthetics directly tap into sleep-promoting neurons in the brain, a study in mice reveals.
The results may help clarify how drugs that have been used around the world for decades actually put someone under. “It’s kind of shocking that after 170 years, we still don’t understand why they work,” says study coauthor Max Kelz of the University of Pennsylvania in Philadelphia.
Most neurons in the brain appear to be calmed by anesthetics, says neuropharmacologist and anesthesiologist Hugh Hemmings Jr. of Weill Cornell Medical College in New York City. But the new results, published online October 25 in Current Biology, show that two common anesthetics actually stimulate sleep-inducing neurons. “It’s unusual for neurons to be excited by anesthetics,” Hemmings says.
In the study, Kelz, Jason Moore, also of the University of Pennsylvania, and colleagues studied the effects of the anesthetics isoflurane and halothane. Mice given the drugs soon became sleepy, as expected. Along with this drowsiness came a jump in nerve cell activity in a part of the brain’s hypothalamus called the ventrolateral preoptic nucleus, or VLPO.
Sleep-deprived bees have difficulty relearning
Everyone feels refreshed after a good night’s sleep, but sleep does more than just rejuvenate, it can also consolidate memories. ‘The rapid eye movement form of sleep and slow wave sleep are involved in cognitive forms of memory such as learning motor skills and consciously accessible memory’, explains Randolf Mezel from the Freie Universtät Berlin, Germany. According to Menzel, the concept that something during sleep reactivates a memory for consolidation is a basic theory in sleep research. However, the human brain is far too complex to begin dissecting the intricate neurocircuits that underpin our memories, which is why Menzel has spent the last four decades working with honey bees: they are easy to train, well motivated and it is possible to identify the miniaturised circuits that control specific behaviours in their tiny brains. Intrigued by the role of sleep in memory consolidation and knowing that a bee is sleeping well when its antennae are relaxed and collapsed down, Menzel decided to focus on the role of sleep in one key memory characteristic: relearning (p. 3981). The challenge that Menzel set the bees was to learn a new route home after being displaced from a familiar path.
Menzel and his colleague Lisa Beyaert provided a hive with a well-stocked feeder and trained the bees to visit the feeder and return home fully laden. Then, when the duo were convinced that the bees had memorized the routine, they cunningly intercepted the bees at the feeder and transported them to a new location before releasing the insects to find their way home. According to Menzel, foragers learn the general lay of the land as novices before specialising in a few well-travelled routes later in their careers. He explains that the displaced bees had to rely on their earlier experiences to learn their new way home. How would loss of sleep affect the bee’s ability to learn the new route? To determine this, Menzel and Beyeart first had to check that the bees could learn the new route and that sleep deprivation hadn’t made them too tired or altered their motivation to forage.
Teaming up with electrical engineer Uwe Greggers, Menzel kitted the bees out with tiny RADAR transponders; the RADAR technology was particularly demanding to operate. Tracking the insects’ progress as they tried to learn the alternative route home, Menzel and his colleagues saw that by the second run home, the displaced bees had learned the new route. And when the trio disturbed the insects’ sleep during the night before the initial displacement by shaking them awake every 5 min, they found that the bees were unfazed. In fact they didn’t seem to need sleep to maintain their foraging energy levels and the foragers that were deprived of sleep before the first displacement run had no problems learning the new route home.
However, when the team disrupted the bees’ sleep after they had allowed the bees a single run along the new displaced route, the lack of sleep played havoc with their memories on the following day. Fewer than half of the sleep-deprived foragers made it home successfully, and those that did took more than twice as long as bees that had enjoyed an uninterrupted night’s sleep.
Sleep deprivation had dramatically affected the bees’ ability to alter a well-established memory and the team is now keen to see whether they can identify characteristic activity patterns in the slumbering insects’ brains that could represent memory formation.
"Blue" Light Could Help Teenagers Combat Stress
Adolescents can be chronically sleep deprived because of their inability to fall asleep early in combination with fixed wakeup times on school days. According to the CDC, almost 70 percent of school children get insufficient sleep—less than 8 hours on school nights. This type of restricted sleep schedule has been linked with depression, behavior problems, poor performance at school, drug use, and automobile accidents. A new study from the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute shows that exposure to morning short-wavelength “blue” light has the potential to help sleep-deprived adolescents prepare for the challenges of the day and deal with stress, more so than dim light.
The study was a collaboration between Associate Professor and Director of the LRC Light and Health Program Mariana Figueiro and LRC Director and Professor Mark S. Rea. Results of the study titled “Short-Wavelength Light Enhances Cortisol Awakening Response in Sleep-Restricted Adolescents,” were recently published in the open access International Journal of Endocrinology. The full text is available at http://www.hindawi.com/journals/ije/2012/301935/.
Scientists read dreams: Brain scans during sleep can decode visual content of dreams
A team of researchers led by Yukiyasu Kamitani of the ATR Computational Neuroscience Laboratories in Kyoto, Japan, used functional neuroimaging to scan the brains of three people as they slept, simultaneously recording their brain waves using electroencephalography (EEG).
The researchers woke the participants whenever they detected the pattern of brain waves associated with sleep onset, asked them what they had just dreamed about, and then asked them to go back to sleep.
This was done in three-hour blocks, and repeated between seven and ten times, on different days, for each participant. During each block, participants were woken up ten times per hour. Each volunteer reported having visual dreams six or seven times every hour, giving the researchers a total of around 200 dream reports.
From the twitching whiskers of babes: Naptime behavior shapes the brain
The whiskers of newborn rats twitch as they sleep, and that could open the door to new understandings about the intimate connections between brain and body. The discovery reinforces the notion that such involuntary movements are a vital contributor to the development of sensorimotor systems, say researchers who report their findings along with video of those whisker twitches on October 18 in Current Biology, a Cell Press publication.
"We found that even whiskers twitch during sleep—and they do so in infant rats long before they move their whiskers in the coordinated fashion known as whisking," said Mark Blumberg of The University of Iowa. "This discovery opens up new avenues for investigating how we develop critical connections between the sensors in our body and the parts of the brain that interpret and organize sensory information."