Mechanisms of Sleep-Dependent Consolidation of Cortical Plasticity
Sara J. Aton, Julie Seibt, Michelle Dumoulin, Sushil K. Jha, Nicholas Steinmetz, Tammi Coleman, Nirinjini Naidoo, and Marcos G. Frank
DOI 10.1016/j.neuron.2009.01.007
Sleep is thought to consolidate changes in synaptic strength, but the underlying mechanisms are unknown. We investigated the cellular events involved in this process during ocular dominance plasticity (ODP)—a canonical form of in vivo cortical plasticity triggered by monocular deprivation (MD) and consolidated by sleep via undetermined, activity-dependent mechanisms. We find that sleep consolidates ODP primarily by strengthening cortical responses to nondeprived eye stimulation. Consolidation is inhibited by reversible, intracortical antagonism of NMDA receptors (NMDARs) or cAMP-dependent protein kinase (PKA) during post-MD sleep. Consolidation is also associated with sleep-dependent increases in the activity of remodeling neurons and in the phosphorylation of proteins required for potentiation of glutamatergic synapses. These findingsdemonstrate that synaptic strengthening via NMDAR and PKA activity is a key step in sleep-dependent consolidation of ODP.
Molecule that helps the sleep-deprived to mentally rebound
Control and Function of the Homeostatic Sleep Response by
Adenosine A1 Receptors
Theresa E. Bjorness, Christine L. Kelly, Tianshu Gao, Virginia Poffenberger, and Robert W. Greene
Department of Psychiatry, University of Texas Southwestern, Dallas, Texas 75390
During sleep, the mammalian CNS undergoes widespread, synchronized slow-wave activity (SWA) that directly varies with previous waking duration (Borbe´ly, 1982; Dijk et al., 1990). When sleep is restricted, an enhanced SWA response follows in the next sleep period. The enhancement of SWA is associated with improved cognitive performance (Huber et al., 2004), but it is unclear either how the SWA is enhanced or whetherSWAis needed to maintain normal cognitive performance.Aconditional, CNS knock-out of the adenosine receptor, AdoA1R gene, shows selective attenuation of the SWA rebound response to restricted sleep, but sleep duration is not affected. During sleep restriction, wild phenotype animals express a rebound SWA response and maintain cognitive performance in a working memory task. However, the knock-out animals not only show a reduced rebound SWA response but they also fail to maintain normal cognitive function, although this function is normal when sleep is not restricted. Thus, AdoA1R activation is needed for normal rebound SWA, and when the SWA rebound is reduced, there is a failure to maintain working memory function, suggesting a functional role for SWA homeostasis.
Adenosine A1 Receptors
Theresa E. Bjorness, Christine L. Kelly, Tianshu Gao, Virginia Poffenberger, and Robert W. Greene
Department of Psychiatry, University of Texas Southwestern, Dallas, Texas 75390
During sleep, the mammalian CNS undergoes widespread, synchronized slow-wave activity (SWA) that directly varies with previous waking duration (Borbe´ly, 1982; Dijk et al., 1990). When sleep is restricted, an enhanced SWA response follows in the next sleep period. The enhancement of SWA is associated with improved cognitive performance (Huber et al., 2004), but it is unclear either how the SWA is enhanced or whetherSWAis needed to maintain normal cognitive performance.Aconditional, CNS knock-out of the adenosine receptor, AdoA1R gene, shows selective attenuation of the SWA rebound response to restricted sleep, but sleep duration is not affected. During sleep restriction, wild phenotype animals express a rebound SWA response and maintain cognitive performance in a working memory task. However, the knock-out animals not only show a reduced rebound SWA response but they also fail to maintain normal cognitive function, although this function is normal when sleep is not restricted. Thus, AdoA1R activation is needed for normal rebound SWA, and when the SWA rebound is reduced, there is a failure to maintain working memory function, suggesting a functional role for SWA homeostasis.
What Happens When You Sleep?
Another nice article from the National Sleep Foundation.
When we sleep well, we wake up feeling refreshed and alert for our daily activities. Sleep affects how we look, feel and perform on a daily basis, and can have a major impact on our overall quality of life.
To get the most out of our sleep, both quantity and quality are important. Teens need at least 8½ hours—and on average 9¼ hours—a night of uninterrupted sleep to leave their bodies and minds rejuvenated for the next day. If sleep is cut short, the body doesn’t have time to complete all of the phases needed for muscle repair, memory consolidation and release of hormones regulating growth and appetite. Then we wake up less prepared to concentrate, make decisions, or engage fully in school and social activities.
How Does Sleep Contribute to All of These Things?
Sleep architecture follows a pattern of alternating REM (rapid eye movement) and NREM (non-rapid eye movement) sleep throughout a typical night in a cycle that repeats itself about every 90 minutes.
What role does each state and stage of sleep play?
NREM (75% of night): As we begin to fall asleep, we enter NREM sleep, which is composed of stages 1-4
Stage 1
* Between being awake and falling asleep
* Light sleep
Stage 2
* Onset of sleep
* Becoming disengaged from surroundings
* Breathing and heart rate are regular
* Body temperature drops (so sleeping in a cool room is helpful)
Stages 3 and 4
* Deepest and most restorative sleep
* Blood pressure drops
* Breathing becomes slower
* Muscles are relaxed
* Blood supply to muscles increases
* Tissue growth and repair occurs
* Energy is restored
* Hormones are released, such as: Growth hormone, essential for growth and development, including muscle development
REM (25% of night): First occurs about 90 minutes after falling asleep and recurs about every 90 minutes, getting longer later in the night
* Provides energy to brain and body
* Supports daytime performance
* Brain is active and dreams occur
* Eyes dart back and forth
* Body becomes immobile and relaxed, as muscles are turned off
In addition, levels of the hormone cortisol dip at bed time and increase over the night to promote alertness in morning.
Sleep helps us thrive by contributing to a healthy immune system, and can also balance our appetites by helping to regulate levels of the hormones ghrelin and leptin, which play a role in our feelings of hunger and fullness. So when we’re sleep deprived, we may feel the need to eat more, which can lead to weight gain.
The one-third of our lives that we spend sleeping, far from being “unproductive,” plays a direct role in how full, energetic and successful the other two-thirds of our lives can be.
When we sleep well, we wake up feeling refreshed and alert for our daily activities. Sleep affects how we look, feel and perform on a daily basis, and can have a major impact on our overall quality of life.
To get the most out of our sleep, both quantity and quality are important. Teens need at least 8½ hours—and on average 9¼ hours—a night of uninterrupted sleep to leave their bodies and minds rejuvenated for the next day. If sleep is cut short, the body doesn’t have time to complete all of the phases needed for muscle repair, memory consolidation and release of hormones regulating growth and appetite. Then we wake up less prepared to concentrate, make decisions, or engage fully in school and social activities.
How Does Sleep Contribute to All of These Things?
Sleep architecture follows a pattern of alternating REM (rapid eye movement) and NREM (non-rapid eye movement) sleep throughout a typical night in a cycle that repeats itself about every 90 minutes.
What role does each state and stage of sleep play?
NREM (75% of night): As we begin to fall asleep, we enter NREM sleep, which is composed of stages 1-4
Stage 1
* Between being awake and falling asleep
* Light sleep
Stage 2
* Onset of sleep
* Becoming disengaged from surroundings
* Breathing and heart rate are regular
* Body temperature drops (so sleeping in a cool room is helpful)
Stages 3 and 4
* Deepest and most restorative sleep
* Blood pressure drops
* Breathing becomes slower
* Muscles are relaxed
* Blood supply to muscles increases
* Tissue growth and repair occurs
* Energy is restored
* Hormones are released, such as: Growth hormone, essential for growth and development, including muscle development
REM (25% of night): First occurs about 90 minutes after falling asleep and recurs about every 90 minutes, getting longer later in the night
* Provides energy to brain and body
* Supports daytime performance
* Brain is active and dreams occur
* Eyes dart back and forth
* Body becomes immobile and relaxed, as muscles are turned off
In addition, levels of the hormone cortisol dip at bed time and increase over the night to promote alertness in morning.
Sleep helps us thrive by contributing to a healthy immune system, and can also balance our appetites by helping to regulate levels of the hormones ghrelin and leptin, which play a role in our feelings of hunger and fullness. So when we’re sleep deprived, we may feel the need to eat more, which can lead to weight gain.
The one-third of our lives that we spend sleeping, far from being “unproductive,” plays a direct role in how full, energetic and successful the other two-thirds of our lives can be.
25 Random Facts about Sleep
The National Sleep Foundation has created a list of 25 random facts about sleep.
- Man is the only mammal that willingly delays sleep.
- The higher the altitude, the greater the sleep disruption. Generally, sleep disturbance becomes greater at altitudes of 13,200 feet or more. The disturbance is thought to be caused by diminished oxygen levels and accompanying changes in respiration. Most people adjust to new altitudes in approximately two to three weeks — from Jet Lag and Sleep.
- In general, exercising regularly makes it easier to fall asleep and contributes to sounder sleep. However, exercising sporadically or right before going to bed will make falling asleep more difficult — from Sleep Tips.
- Divorced, widowed and separated people report more insomnia — from Sleep Aids and Insomnia.
- Six in ten healthcare professionals do not feel that they have enough time to have a discussion with their patients about insomnia during regular office visits — from the Sleeping Smart Sleep Report Card.
- More than eight in ten survey respondents think that people often or sometimes misuse prescription sleep aids — from the Sleeping Smart Sleep Report Card.
- Caffeine has been called the most popular drug in the world. All over the world people consume caffeine on a daily basis in coffee, tea, cocoa, chocolate, some soft drinks, and some drugs — from Caffeine and Sleep.
- In general, most healthy adults need seven to nine hours of sleep a night. However, some individuals are able to function without sleepiness or drowsiness after as little as six hours of sleep. Others can’t perform at their peak unless they’ve slept ten hours — from ABC's of ZZZZs — When You Can't Sleep.
- We naturally feel tired at two different times of the day: about 2:00 AM and 2:00 PM. It is this natural dip in alertness that is primarily responsible for the post-lunch dip — from Ingredients for Slumber: How Food and Beverages May Affect Your Sleep.
- Sleep is just as important as diet and exercise.
- According to the International Classifications of Sleep Disorders, shift workers are at increased risk for a variety of chronic illnesses such as cardiovascular and gastrointestinal diseases.
- Newborns sleep a total of 10.5 to 18 hours a day on an irregular schedule with periods of one to three hours spent awake — from Children and Sleep.
- When infants are put to bed drowsy but not asleep, they are more likely to become "self- soothers," which enables them to fall asleep independently at bedtime and put themselves back to sleep during the night — from Children and Sleep.
- Eighty-two percent of healthcare professionals believe that it is the responsibility of both the patient and the healthcare professional to bring up symptoms of insomnia during an appointment — from the Sleeping Smart Sleep Report Card.
- The body never adjusts to shift work!
- There are individual differences in the need to nap. Some adults and children need to nap. However, the majority of teenagers probably nap in the afternoon because they are not sleeping enough at night — Daniel Lewin, PhD, Ask the Sleep Expert: Sleep and Teens.
- Snoring is the primary cause of sleep disruption for approximately 90 million American adults; 37 million on a regular basis — from Aging and Sleep.
- Scientists still don't know — and probably never will — if animals dream during REM sleep, as humans do — from Dreams and Sleep.
- Some studies show promise for the use of melatonin in shortening the time it takes to fall asleep and reducing the number of awakenings, but not necessarily total sleep time. Other studies show no benefit at all with melatonin — from Melatonin and Sleep.
- One of the primary causes of excessive sleepiness among Americans is self-imposed sleep deprivation — from Excessive Sleepiness and Sleep.
- According to the results of NSF's 2008 Sleep in America poll, 36 percent of American drive drowsy or fall asleep while driving.
- According to the results of NSF's 2008 Sleep in America poll, a surprising 34 percent of respondents reported their employer allows them to nap during breaks and 16 percent provide a place to do so.
- People who don’t get enough sleep are more likely to have bigger appetites due to the fact that their leptin levels (leptin is an appetite-regulating hormone) fall, promoting appetite increase — from Diet, Exercise and Sleep.
- Rates of insomnia increase as a function of age, but most often the sleep disturbance is attributable to some other medical condition — from the Sleeping Smart Study Hall.
- And in case you missed our post on Tips for Beating the Winter Blues, did you know seasonal affective disorder is believed to be influenced by the changing patterns of light and darkness that occur with the approach of winter?
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