To sleep is to reinvigorate yourself. Vital functions are carried out when you sleep, and your brain embeds a lot of the information you have learned throughout the day. Dreams are a chaotic, sometimes fun, sometimes terrifying byproduct of sleep that psychologists have investigated for some time, including famous names like Freud. Sleep and dreaming naturally come hand in hand, and we need to know the different functions, stages, and disorders of sleep.
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Sign up for freeEndogenous pacemakers are ______ influences on our biological rhythm.
Exogenous zeitgebers are ______ influences on our biological rhythm.
A circadian rhythm is one that occurs once every 24 hours, true or false?
Siffre spent _ months in a cave to study the sleep-wake cycle.
An example of an endogenous pacemaker is:
Sleep ___ brain development.
On average, we sleep for __ years during our lifetime.
Stage two in the sleep cycle is characterised as ___ sleep.
Endogenous pacemakers are ______ influences on our biological rhythm.
Exogenous zeitgebers are ______ influences on our biological rhythm.
A circadian rhythm is one that occurs once every 24 hours, true or false?
Siffre spent _ months in a cave to study the sleep-wake cycle.
An example of an endogenous pacemaker is:
Sleep ___ brain development.
On average, we sleep for __ years during our lifetime.
Stage two in the sleep cycle is characterised as ___ sleep.
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Sleep and dreaming often go hand-in-hand; people sleeping vector created by storyset - www.freepik.com.
Sleep is one of the most fundamental aspects of life. We can define sleep, according to the American Psychological Association (APA)¹ as:
a circadian state characterised by partial or total suspension of consciousness, voluntary muscle inhibition, and relative insensitivity to stimulation.
We define dreams as¹:
a physiologically and psychologically conscious state that occurs during sleep and is often characterised by a rich array of endogenous sensory, motor, emotional, and other experiences.
The functions of sleep have been highly discussed and researched by psychologists and medical researchers alike. We spend 230,000 hours, or around 26 years, sleeping in our lifetime. Surely something that takes up that amount of time must be important, right?
What we can say about sleep is that sleep aids brain development. Sleep helps our mental health, physical well-being and health, including supporting our immune systems and weight management in addition to our cognitive functioning, such as language, speech, and memory. Sleep releases growth hormones for bodily repair after a hard day's work, and memories are consolidated so you can remember all of the information you learn during the day.
When we are low on sleep, our cognitive and physical functions decline quite heavily:
Full sleep deprivation can result in death, although we still don't know how long people can go without sleep before this occurs.
Although it may seem not much is happening during sleep, it is an important and hard-working function that keeps the brain and body in good shape.
There are four stages of sleep and REM sleep, although there is some debate on whether there is a proper distinction between the third and fourth stages of sleep. All stages go through around five cycles, each lasting approximately 90 minutes.
Brain wave activity changes in different stages of sleep²
Bodily rhythms are where we can see the influences on sleep. The sleep-wake cycle is an example of a circadian rhythm, which occurs once every 24 hours. The sleep cycle of four stages and REM sleep, which we discussed above, is an example of ultradian rhythm, which happens more than once in 24 hours.
Be careful not to confuse the sleep-wake cycle and the sleep cycle!
Internal influences on sleep are known as endogenous pacemakers, and external influences on sleep are known as exogenous zeitgebers.
Endogenous pacemakers are internal controls on our biological rhythms, whereas exogenous zeitgebers are external controls or cues that affect our biological rhythms.
An example of an endogenous pacemaker can be seen in the suprachiasmatic nucleus (SCN), which signals the pineal gland to release melatonin when the eye perceives less light.
An example of an exogenous zeitgeber can be seen in light and how light levels affect our sleep cycle. The SCN is internally controlled, and light is an external cue that affects internal control.
Siffre (1975) spent six months in a cave investigating bodily rhythms and how they proceed when in the absence of natural external cues (exogenous zeitgebers). NASA was invested in this study as they wanted to understand how this would impact astronauts undergoing space travel.
Siffre found that his emotional state declined; he felt lonely and started to entertain thoughts of suicide. Siffre's health was also impacted; his eyesight worsened, and his memory suffered. His sleep-wake cycle changed from the usual 24 hours to between 18 and 52 hours.
When exogenous zeitgebers are no longer able to provide external cues to the body to sleep, the circadian rhythm struggles to keep up, although it was possible to some extent.
Sleep disorders include insomnia and narcolepsy.
Insomnia is the inability to fall asleep, whereas narcolepsy is characterised by sudden episodes of sleep attacks that can occur randomly throughout the day. Narcolepsy is a struggle to control the aforementioned sleep-wake cycle.
Insomnia symptoms include:
There are different types of insomnia; sleep onset insomnia is the struggle to fall asleep, whereas sleep maintenance insomnia is the struggle to stay asleep.
Narcolepsy symptoms include:
Insomnia can be explained or affected by lifestyle choices, health conditions, sleep hygiene, food, drinks, or medications. Narcolepsy can be explained or affected by low levels of hypocretin (orexin), a neuropeptide that regulates wakefulness, genetic heritability, and stress. Some suggest an evolutionary advantage to narcolepsy by highlighting the usefulness of muscle tone loss in survival situations.
We can improve sleep by focusing on improving our sleep hygiene habits. Sleep hygiene includes:
Treatment for insomnia and narcolepsy includes improving sleep hygiene.
As we defined above, dreaming is a state of unconsciousness characterised by fantastical, nonsensical experiences. There are multiple theories on dreaming, with two fundamental ideas taking centre stage:
Freud's theory of dreaming centres around his ideas on the conscious and unconscious mind and how the three factors of our personality (the Id, ego, and superego) interact and suppress one another. The unconscious mind is where our, often secret, desires lie.
Freud placed importance on analysing dreams to understand a patient's mental health.
Dreaming, according to Freud, is seen as a means to fulfil a person's unconscious desires - wish fulfilment - as the ego, the reality principle suppresses the more primitive urges of the Id, is weakened. The weakened state of the ego allows the unconscious desires to seep through, and our dreams are our desires realised in unconscious form.
Freud described dreams through latent and manifest content:
However, our desires are sometimes disturbing, so to protect the mind from being bombarded by primitive urges, dreamwork hides the content of our dreams through condensation, displacement, and secondary elaboration.
The Wolfman study is a case that supports Freud's theories. However, many do not consider the Wolfman study to be sufficient evidence. The "wolfman" himself described Freud's views on his dreams as outlandish.
Freud's Wolfman study supported that unconscious, hidden messages manifest in our dreams, vector created by inventorsolutions - www.freepik.com.
The activation-synthesis theory of dreaming takes a more biological approach to explain why we dream.
According to the activation-synthesis theory of dreaming, dreams are a byproduct of brain activation that occurs when we sleep. It is our mind's way of trying to make sense of these activations and combine them into understandable dreams.
The cerebral cortex interprets nerve impulses that are occurring in the brain stem.
The mind synthesises dreams during the activation of specific regions of the brain during REM sleep, and these areas are often involved in:
The activation-synthesis theory can also explain why dreams can be illogical, only make sense to the dreamer, and often are lost when they wake up.
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Is sleep with dreams a good sleep?
Sleep with dreams is a naturally occurring part of the sleep cycle and indicates REM sleep has taken place. Sleep with dreams can be considered beneficial as memory consolidation occurs. The content of the dreams may affect the quality of sleep. For example, nightmares can be problematic for some.
What is the relationship between sleep and dreams?
Dreams are a natural part of the sleep process and typically occur during the REM stage of sleep. Whilst not all people remember their dreams, they are heavily connected and reliant on sleep.
How are sleep and dreams important?
Lack of or the absence of sleep can be detrimental to a person's health. Sleep is vital for brain development, and during sleep, growth hormones are released for body repair, neurotransmitters balance out, and memories are consolidated.
Dreams are a natural part of the sleep process, and many theories suggest there is importance to dreams (Freud's theory of dreams) or that dreams are a byproduct of brain activation during sleep (activation-synthesis model).
Which sleep is better with dreams or without dreams?
Sleep quality depends on the sleep cycle rather than dream content and presence. Sleep is better when a person undergoes, on average, five cycles of the four stages of sleep and REM sleep, with each cycle lasting 90 minutes. REM sleep is typically where vivid dreams occur, and dreams are a normal, healthy part of sleep. Dreams are not always remembered.
Why we sleep and dream?
We sleep to allow the body to rest and repair itself. Growth hormones repair the body during sleep, and neurotransmitter levels balance themselves, among other vital cognitive developmental functions. Sleep deprivation can negatively impact cognitive functioning.
Why we dream has been asked by many researchers. Freud suggested dreams are a means of wish fulfilment. In contrast, the activation-synthesis theory suggests dreams are a byproduct of brain activation during sleep.
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