5.1: The Biology of Sleep

Our sleeping and waking experiences are very different.

30-50 percent of our waking hours are spent mind-wandering, fantasizing, and thinking about another thing (Killingsworth & Gilbert, 2010; Klinger, 2013; Smallwood & Schooler, 2015).
Fantasy is an escape from reality.
fantasies and daydreams are normal and can help us plan for the future, solve problems, express our creativity, and refresh us by providing a break from routine and boring tasks.

Sleep paralysis has been reported in many threats efficiently and unconsciously.

Visitors ranging from an "old hag" to members of the animal kingdom can have altered awareness and ability to control it.

The eye on the side opposite the sleeping hemisphere is usually closed.

The other hemisphere takes over as sleep continues.
The arrangement permits these animals to sleep while being on the lookout for obstacles as well as to rise periodically to the surface of the water to breathe.

During up to 10 days of nonstop flights, researchers have discovered that great frigate birds sleep with both hemispheres switched off, allowing them to keep one eye open to be alert to threats.

In this chapter, we'll see examples of how the spotlight of our awareness and level of alertness changes constantly and how consciousness is sensitive to changes in our brain chemistry, expectations, and culture.

As we consider the critical question of how our subjective experience of the world and ourselves develops and changes on a moment-to-moment basis, we'll come to appreciate how scientists are using high-tech tools to measure neural events and explore the most basic biological processes that sculpt our stream.

We'll look at how the unity of consciousness can break down in unusual and sometimes fascinating ways, such as during sleepwalking, when we're unconscious yet move about as if awake, and when we feel as though we're reliving an event we've never experienced.

They can appear unconscious to onlookers because their muscles are paralyzed, rendering them unable to speak or move.
The famous Parisian journalist Jean-Dominique Bauby had a stroke.
He wrote a memoir using a special alphabet code devised by his therapist and blinking his eye to dictate one letter at a time, underscoring the ability of people to adapt under the most trying of circumstances.
In psychology, abnormality in functioning can often shed light on normal functioning.

There are features and causes of sleep disorders.

As much as one-third of our lives is spent in one state of consciousness.
We don't mean to stop listening to the lecture.
Although it's clear that sleep is important to our health and daily functioning, psychologists still don't know why we sleep.
Some believe that sleep plays a critical role in new learning, storing memories, and remembering emotional information, while others think it's important for the immune system.
The possible role of sleep in promoting insight and problem solving is one of the models that emphasizes it.
According to J. Allan Hobson, brain activation during sleep is essential to waking consciousness and our ability to plan, reason, and function to the best of our ability.
Evolutionary theorists suggest that sleep contributes to our survival by taking us out of circulation at times when we might be most vulnerable to unseen predators, and restoring our strength to fend them off.
Some of these explanations may be true.

Before scientists began to study the secrets of sleep in the laboratory, primitive hunters were aware of daily cycles of sleep and wakefulness.

Many of us feel like we take a nap in the afternoon.
Our biological clocks cause this sense of fatigue.

When humans' biological clocks are disrupted, such as when we work late shifts or travel across time zones and experience jet lag, it disturbs sleep and increases the risk of injuries, fatal accidents, and health problems.

The trail of drugs that target melatonin in the brain to resync our brain's biological clock is being pursued by scientists.
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According to a recent survey of more than 320,000 respondents, the average U.S. adult sleeps 7.18 hours, but less than 10 hours a night.

Newborns need about 16 hours of sleep a day.

Only a small percentage of the population carry a gene that allows them to get away with sleeping six hours or less a night without "crashing" the next day.
College students may need as much as nine hours of sleep a night, although most sleep no more than six hours, creating a powerful urge to nap the next day.
The elderly don't need as much sleep as the rest of us, only six or seven hours a night.
They probably don't need as much sleep as they think.

Losing one night's sleep doesn't seem to have a lot of negative consequences other than being tired the next day.

After a few nights of sleep deprivation, we feel more "out of it" and begin to accumulate a balance of "sleep debt" which can require at least several nights of sleeping a few extra hours to pay off.
People deprived of multiple nights of sleep, or who cut back drastically on sleep, often experience mild depression, difficulties in learning new information and paying attention, problems in thinking clearly, solving problems, and making decisions, increased emotional reactivity, and slowed reaction times.
After more than four days of sleep deprivation, we may experience brief hallucinations, such as hearing voices or seeing things.
There are a variety of adverse health outcomes associated with sleep deprivation: weight gain, increased risk for high blood pressure, diabetes, and heart problems, and a less vigorous immune response to viral infections.
The last effect explains why you're more likely to get a cold when you go for several days to a week with little sleep.
Although this claim is controversial, some researchers believe that the increase in obesity and diabetes in the United States over the past few decades is due to Americans' chronic sleep deprivation.

The tragic crash of Colgan Air Flight 3409 of sleep has been tied to friendly-fire incidents in the 1991 Persian Gulf War, as both the soldiers which mistook their colleagues for the enemy, resulted in unnecessary deaths.

Recent data shows that African Americans are less likely to sleep well than Caucasians.

There are no clear reasons for this difference.
It remains even after taking into account differences between African Americans and Caucasians in social class and education, so other factors, like race differences in everyday life stressors, appear to be at play.

"Anything in moderation" is what many of our parents counseled us to do.

Moms and dads worry about their teenagers.
The parents of 15-year-old Louisa Ball, who lives in south England, were concerned for another reason; their daughter slept for two weeks without interruption unless she received medication.
Her parents have to wake her every 22 hours to feed her and take her to the bathroom so she can sleep.

For a long time, people believed that there was a switch in our brains that made us sleepy when we were awake.

The 1951 discovery in Nathaniel Kleitman's sleep laboratory at the University of Chicago changed how we think about sleep and dreaming.
Eugene Aserinsky monitored his eight-year-old son's brain waves and eye movements while he slept.
Aserinsky was astonished to see that his son's eyes were moving.
The electrical activity in the boy's brain was the same as it was when he was awake.

The scientist had good reason to know that he was important.

The brain was abuzz with activity at various intervals.
Aserinsky suspected that his son was dreaming.

They reported vivid dreams.

When researchers woke participants up from sleep when they weren't displaying REM, they were less likely to report vivid dreams because darting of the eyes underneath closed participants were much less likely.

Kleitman and William Dement (Dement & Kleitman, 1957) discovered that during sleep we pass through five stages.

Your friend insisted, "Yes, you were," even though you might have said, "No, I wasn't really sleeping."

Stage 1 sleep is when you are most likely in.

When we're quiet and relaxed, the waves are called bier waves.

There are images that arescrambled, bizarre, and dreamy.

Stage 1 is when our limbs are startled.

We're usually quite confused in this state of sleep.

Stage 3 and 4 and occasional K-complexes first appear in the EEG after a sudden intense burst of electrical activ and K complexes.

When we're asleep, K-complexes don't appear.

The Delta Waves movements stopped.

65 percent of our REM sleep is spent in stage 2.

Delta waves appear among the major stages of sleep, along with two levels of 20 to 50 percent of the time, and in stage 4 they appear more wakefulness.

Brain activity during REM sleep is less than half the time.
In recent years, researchers have tended to be similar to that when we're awake and alert because our brains are engaged in vivid dreaming during sleep stages 3 and 4.

We need deeper sleep throughout the night to feel rested in the morning.

A common myth is that drinking alcohol can help you catch up on sleep.
When we have drinks before bed, it usually puts us to bed sooner, but it also makes us feel tired the next day.
Children spend as much as 40 percent of their sleep time in deep sleep and are difficult to awaken.
Adults only spend 25% of their sleep in deep sleep.

After 15 to 30 minutes, we return to stage 2, where our brains shift into high gear with high frequencies and lowamplitude waves.

Our brain waves during REM sleep are accompanied by increased heart rate, which is the most active, as well as rapid and irregular breathing, a state that occupies about 25% of our night's sleep.

We circle back to sleep five or six times a night.
Our later REM periods last for less than an hour and a half, compared to the 10 to 20 minutes we spend in REM after fall.
It's often because it seems like one of your dreams has lasted for 45 minutes.

As the night wears on, dream reports from NREM sleep (starting with stage 2) resemble REM dream reports, leading some researchers to suggest that REM and NREM dreams aren't as distinct as once believed.

REM sleep is important.

Rats of REM sleep are more likely to die within their dreams than non-REM rats.

The National Institute on Alcohol Use and Alcoholism would be more likely to have a dream in a few weeks.

When we haven't slept much for a few nights in a row, REM will rebound.

When we get a good night's sleep, we often experience more intense dreams, even nightmares, reflecting a lack of REM sleep.
The biological functions of REM sleep are still being debated.

Some researchers believed that the darting movements of REM sleep could be used to look at dreams.

A person during REM engaged in a striking pattern of back-and-forth horizontal eye movements.
He had a dream of a Ping-Pong match.

The fact that individuals who are blind engage in REM calls into question the evidence for the scanning hypothesis.

The muscles of our middle ears become active during REM, almost as if they're helping us to hear sounds in the dream.

Our brains are making dreams, but our bodies are relaxed and paralyzed for practical purposes.

A 77-year-old minister acted out violent dreams in his sleep for 20 years and sometimes injured his wife.

The percentage ofRBD climbs as high as 2 percent for people older than the age of 60 and as high as 6 percent for people older than the age of 70.

Raters of videos of sleeping people who experienced episodes ofRBD successfully matched the movements they observed with the content of dreams that participants reported, suggesting that people withRBD are acting out their dreams.

The brain stem structures that prevent us from moving during REM sleep don't function properly in RBD.

RBD may be a very early marker of dementia and Parkinson's disease, with it emerging an average of 14 to 25 years before major symptoms of neurodegenerative diseases first appear.

How do you think this would affect the dreams?

We've been talking about sleeping and waking as separate stages, but they may blend into one another.

Less than 5 percent of Americans dream on a weekly basis, and one-fifth of Americans dream on a monthly basis.

When a person sees something so strange that they think they're having a dream, they become aware they're dreaming.

Researchers found that when participants experience a dream, parts of their cerebral cortex associated with selfperceptions and evaluating thoughts, revved up with activity.

A study that measured electrical activity in the brain suggested that dreams are a hybrid state of consciousness with features of both waking and REM sleep.

We don't just report that dreams have a quality after we awaken, but that they have a replicability.

The ability to become lucid during a nightmare usually improves the dream's outcome.

There is no evidence that changing our dreams can help us overcome depression, anxiety, or other adjustment problems, despite the claims of some popular psychology books, Internet sites, and even telephone applications.

Most of us have trouble falling asleep or staying asleep.

When sleep problems recur, they can affect our ability to function at work or school, or affect our health.

The cost of sleep disorders in terms of lost work productivity alone amounts to as much as $63 billion per year in the United States.
1,500 Americans are killed each year when they fall asleep at the wheel, and we can measure the cost in terms of human lives.
It's understandable that 30 to 50 percent of people report some sort of sleep problem.

To make sure the effects of sleeping are taken care of.

Insomnia is the most common sleep problem.
An estimated 9 to 15 percent of people have a lot of time to sleep before they have problems with insomnia.

According to Shahly et al., insomnia is associated with 7.2 percent of costly workplace accidents and errors.

Short bouts of insomnia are often the result of stress and relationship problems, medica tions and illness, working late or variable shifts, jet lag, drinking caffeine, or napping during the day.

If we become frustrated and anxious when we can't fall asleep right away, insomnia can become recurrent.
Most people don't know that it takes 15 to 20 minutes to fall asleep.
If you can't fall asleep quickly, hide clocks, sleep in a cool room, go to sleep and wake up at regular times, and avoid caffeine, then you should try the following recommendations.

Sleeping pills can help with insomnia.

Although brief psychotherapy is more effective than a sleeping pill, it can be combined with medication for insomnia.

Lunesta, a popular sleeping medication, can cause amnesia for events that occur after taking it.

There are indications that Ambien is associated with an increased risk of developing dementia, with higher doses associated with increased Lucas Carlton.

Longstanding use of many sleeping pills can create dependency and make it harder to sleep in England once people stop taking them.

Sleeping pills can cause narcoleptic states.

In the case of a patient with a sleeping disorder, the urge to sleep can strike at any moment, as in the case of the patient who fell asleep in the shower while driving.

He couldn't stay awake while working as a prison guard.
He was afraid his boss would fire him and stifled a yawn.

According to this striking example, the symptoms of narcolepsy can interfere with day-to-day functioning and be quite disturbing, so it's not surprising that nearly 20 percent of people with narcolepsy suffer from serious depression or social anxiety disorder.

People can fall if their muscles become limp as a rag doll.

There are healthy people during REM sleep.

Even though they can't move, people with cataplexy remain alert.

Ordinarily, people who fall asleep don't enter REM sleep for more than an hour.

When people who experience an episode of narcolepsy doze off, they plummet into REM sleep immediately, suggesting that it is the result of a sleep-wake cycle that is badly off-kilter.
It is possible that REM intrusions are a cause of brief waking hallucinations.

Some people develop narco lepsy after a brain tumor or an accident that causes brain damage due to genetic abnormality.

People with narcolepsy have very few brain cells that produce the drug.

One day, a medication that mimics the effects of the brain may cure the disease.
Some dogs suffer from a neurological condition.

In 2008, a 53-year-old Go Airlines captain and his copilot fell asleep during the flight and failed to respond to air traffic controllers for nearly 20 minutes before they woke up.

The problem causes people with apnea to snore loudly, gasp, and sometimes stop breathing for more than 20 seconds.

The person is tired the next day because they can't breathe during the night and interfere with sleep.

Most people with sleep apnea don't know about the multiple awakenings.

A lack of oxygen and the build up of carbon dioxide can lead to many problems, including night sweats, weight gain, fatigue, hearing loss, and an irregular heartbeat, which can increase the risk for dementia or other cognitive impairments.

The dangers of sleep apnea were highlighted in a 10-year study.
The researchers found that the disorder increased the risk of death by 17 percent in men 40 to 70 years old.

Doctors often recommend weight loss as a first treatment option for apnea because it's associated with being overweight.

Air flow passage is blocked by a facemask attached to a machine that blows air into their nose, forcing the airway to remain open.
It can be difficult to adjust to this machine.

Night terrors are more frightening to onlookers than to people who sleep.

Parents can't believe that a child doesn't remember what happened.
Screaming, crying, perspiring, confusion, and wide-eyed, the child may fall back into a deep sleep.
Such episodes usually last for a few minutes, although they may seem like an eternity to a distraught parent.