The awareness that we have of ourselves, our internal states, and the environment is called consciousness.
A state of consciousness allows us to evaluate the environment, while being aware of the occurrence of this complex process.
Being alert is a state of consciousness.
Alertness and the associated state of arousal involve being attentive to our surroundings.
It is something that we often take for granted; however, many patients who arrive in an emergency room are not alert for various reasons, arriving in a so-called altered state of consciousness.
This can be a result of head injuries, toxins, or other medical conditions.
Depression, attention deficit disorder, and chronic fatigue syndrome are some of the disorders that impair the ability to be alert.
It is not possible to maintain a heightened state of alert indefinitely without these disorders.
The brainstem has structures that control alertness and arousal.
The reticular formation is also known as the reticular activated system.
The nature of consciousness has been debated for hundreds of years.
A stream of consciousness was spoken of by William James.
In order to adapt to the world, consciousness is a mental reality that we create.
Automatic processes, such as breathing or the beating of the heart, are often referred to as the unconscious level.
The brain tells them to occur, but they don't happen as a result of conscious intervention.
Sigmund Freud referred to the unconscious as an area of mental life that has a huge impact on our thoughts, feelings, and behaviors, but which is only indirectly accessible, through symptoms, slips of the tongue or physical accidents, and dreams.
Two important functions are served by consciousness.
Keeping track of ourselves, our environment, and our relationship with the environment is a responsibility of consciousness.
Our responses to the information gathered by this monitoring are planned by consciousness.
We think of ourselves as fully conscious, but there are lower levels of consciousness.
Information that is available to consciousness but not always in consciousness can be found at the preconscious level.
This is the location where directions to frequently visited places might be kept.
Many automatic behaviors are stored in the preconscious.
You can do a lot of things without thinking, such as riding a bicycle.
We can start consciousness from controlled processing, where we are aware of what we are doing, and move on to automatic processing, where we perform tasks mechanically.
We can regain consciousness in a moment through daydreaming and meditation.
At the far end of the spectrum is coma and unconsciousness.
The altered state of consciousness is called sleep.
Scientists don't understand the function of sleep.
There is a theory that says sleep is necessary.
The chemical in the body should be associated with sleep if the theory is correct.
A definitive cause-and-effect relationship between a brain chemical and the control of sleep has not been demonstrated.
Evolutionary theories of sleep are based on them.
Our ancestors who survived to pass on their genes were awake during the day and asleep at night, according to this point of view.
Our nocturnal ancestors were more likely to die off before passing on their genes, as their visual system was not built to survive at night and avoid nocturnal predators.
In addition to conducting chemical investigations of sleep, psychologists look at the functions of sleep in animals and humans.
The need for sleep is very strong and it is difficult to deprive organisms of it.
The second cycle without sleep is more difficult than the first.
By the third 24-hour cycle, there can be both delusions and hallucinations.
Four 24-hour cycles of sleep deprivation can cause paranoia.
The symptoms of sleep deprivation disappear when the person is allowed to sleep again.
It is possible to investigate the pattern of sleeping.
Humans sleep at night when the world is in darkness.
People who live in extreme northern or southern Exposures try to create conditions of darkness in order to sleep.
Our body temperature and other markers follow a day-to-night pattern.
Body temperature starts to rise as the morning approaches, peaks during the day, and then begins to fall before sleep at night.
Although this is a general description of the flow of alert throughout the day, it varies by individual and age.
A newborn can sleep for two-thirds of the day.
Older adults tend to peak in the morning and decline as the day progresses, while adolescents and young adults tend to be more energetic in the late evening.
Light, both natural and artificial, can affect the biological clock.
The brain's pineal gland is responsible for melatonin production.
This natural day-night rhythm is due to the relationship of the Earth and the Sun.
Our rhythms match this pattern.
If all time cues are removed, we tend to follow a 25-hour rhythm called a free-running rhythm.
Our rhythms are set by external stimuli.
In the case of traveling across time zones, rapid changing of stimuli can affect the rhythms of the body.
The unpleasant feelings associated with jet lag can be found in this example.
Sleep is not a uniform process.
Brain-wave patterns can be used to divide sleep into stages.
Brain waves can be measured withEEGs, which show the electrical activity of the brain.
When we are awake, there is activity in the waves.
We drift into alpha waves while still awake.
Theta wave activity takes over when we drift off to sleep.
Stage 2 sleep has a pattern of waves known as sleep spindles.
K complexes are large, slow waves and sometimes they break up the spindles.
The muscles relax during sleep.
Delta waves are most common in stages 3 and 4.
REM sleep is the last stage of sleep.
The eyes are relatively still in all other stages of sleep, which are collectively referred to as NREM or non-REM sleep.
During the REM stage, the eyes move vigorously.
It is not the only stage of sleep in which dreaming occurs.
Our brain waves are mostly theta and beta in REM sleep.
The fact that this is a very deep stage of sleep, characterized by suppressed skeletal muscle tone, but in which our brain waves resemble those observed when we are nearly awake, has led investigators to refer to REM sleep as paradoxical sleep.
If we sleep seven and one-half hours, we will experience 5 sleep cycles.
Stage 3 and 4 disappear as the period of sleep progresses.
When the dreams are less than an hour long, the REM or dream sleep gets longer.
Dreams occurring toward the end of sleep are easier to remember because they are close to an awakened state.
The big difference in sleep is between REM and non-REM.
William Dement studied the effects of REM sleep deprivation.
When participants were deprived of REM sleep, their REM periods increased from the normal 90 minutes of REM per night to 120 minutes of REM sleep in the period immediately following the deprivation.
REM rebound helps reinforce the idea that we need to sleep.
Like sleep itself, dreams are mysterious.
We all dream, but we don't always remember our dreams and the function of dreams is unknown.
Freud thought that dreams were expressions of unconscious wishes.
The storyline and imagery of the dream can offer insight into unconscious processes.
The underlying meaning of the dream is the emotional significance.
According to the activation-synthesis hypothesis, dreams are the product of our awareness of neural activity while we are sleeping.
You may dream of a waterfall if it starts raining while you are sleeping.
According to the problem-solving theory of dreaming, dreams give the mind a chance to work out issues that occupy it's attention during waking hours.
Neural repair, consolidation of memories, andProtein seem to occur in dreams.
A nightmare is an elaborate dream sequence that can cause a high level of fear for the dreamer.
The dreamer might feel a sense of physical danger to himself or his loved ones, or a sense of embarrassment about doing something that's not right.
These dreams are vivid and can be elaborately described by the dreamer upon waking up.
It is not surprising that psychologists are interested in disorders of sleep, given that sleep is such an important factor in our lives.
Irregularities in the amount, quality, and timing of sleep are called dyssomnias.
The most common sleep disorders are insomnia and inability to fall asleep.
Chronic stress and alcohol use can cause insomnia.
The inability to stay awake is called narcolepsy.
A narcoleptic has an irresistible desire to sleep throughout the day and at inappropriate times.
When narcoleptics fall asleep, it is usually only for a few minutes, and the rest is REM sleep.
The cause of the disorder is not known.
Recent research suggests that the cause of narcolepsy is a malfunction in the region of the hypothalamus that makes the neurotransmitter hypocretin.
Sleep Apnea is a disorder in which a person stops breathing while sleeping and wakes up without air.
It can happen hundreds of times in a night, leaving the person exhausted during the day.
Alcohol consumption may be linked to sleep apnea.
SIDS may be linked to sleep apnea.
Sleepwalking and night terrors are related to parasomnias, which involve abnormal movement during deep sleep.
Sleepwalking occurs when an individual walks around while sleeping.
Scientists have shown that sleepwalking is more than just acting out dreams during stage 3 and 4 sleep.
Night terrors involve actual behaviors such as screaming, crying, and jerking/lunging movements while asleep.
A person who is suffering a night terror may be quite mobile, going through all the motions of being attacked, and yet being fully asleep.
There is usually no recollection of these actions later on.
The hypnotized person is very relaxed and open to suggestion.
People can be impregnated with the idea that they can see things that aren't there or experiences that aren't happening.
When they are in a normal state of consciousness, phenotized individuals can sometimes recall things that they can't remember.
A person who is hypnotized has no recollection of the experience.
Some people think that hypnotism is a state of deep relaxation, while others think that it is a form of living up to the expectations of the hypnotist or experimenter.
The neodissociative theory is a theory of hypnotism.
Hilgard's theory of the hidden observer states that hypnotism divides the mind into two parts.
One part obeys the hypnotist, while the other part silently observes everything.
The theory of hypnotism is unexplained.
Explaining hypnotism is more difficult due to the fact that some people are more susceptible to hypnotism than others.
There are some clinical applications for hypnotism.
In some types of therapy, hypnotism is used to get bad memories out of the unconscious mind.
It is questionable if repressed memories are valid.
In a legal setting, reports of repressed memories may be questionable and have been used to accuse people of crimes they did not commit.
People who are hypnotized may be vulnerable to posthypnotic suggestion.
Posthypnotic suggestions are instructions given to people after they are hypnotized.
Suggestions to treat chronic pain, reduce blood pressure, and even help people quit smoking have had limited success.
A variety of techniques, many of which have been practiced for thousands of years, are referred to as meditation.
Meditators can focus on a single thing, such as their breathing, or they can broaden their attention and be aware of multiple stimuli.
Pain, stress, and anxiety disorders have been successfully managed with meditation.
In the medical setting, MBSR is used to help alleviate stress.
Meditators have increased alpha and theta waves while they are meditating, with more experienced meditators showing greater improvements.
It is important to distinguish between dependence, tolerance, and withdrawal when discussing psychoactive drugs.
Dependence occurs when an individual continues using a drug despite the negative consequences in order to avoid unpleasant physical and/or psychological feelings associated with not taking it.
Similar to physical dependence, psychological dependence is biologically based.
The nucleus accumbens, the "pleasure center" of the brain, are active in dopamine circuits.
The dopaminergic pathway leads to feelings of reward and pleasure.
The release of dopamine in the nucleus accumbens is stimulated by many addictive drugs.
They are effective because they have the same resemblance to the pain relief and euphoria chemicals found in the brain.
A person has developed tolerance to a drug when larger amounts are needed in order for the same effect to occur.
tolerance can be developed without being dependent.
The process of withdrawing from a drug involves physical and psychological symptoms that can be very unpleasant.
Chapter 19 has answers and explanations.
Subliminal perception is when stimuli are presented too quickly for us to be aware of them.
A dependence on alcohol can cause an individual to stop drinking.
Seizures are one of the symptoms of withdrawal.
A patient goes to the doctor's office complaining of being sleepy in the night and tired during the day.
A woman is on medication.
Over the past three years, her dose has increased twice.
Her blood pressure goes up if she forgets to take her medication.