Sleep Patterns

Sleep Patterns
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A figure depicting the sleep cycles in a single night's sleep in addition to the brain wave
patterns during a sleep with the interpretations of each neuronal oscillation included. [7]

When talking about sleep patterns, there are many things that might come to mind; patterns during the daytime are one type, patterns of sleep stages during a single sleep are another and finally brainwave patterns during different stages of sleep/wakefulness. Each one of those possible interpretations has many subtopics that could be considered. Regarding daily sleep patterns, there are two different approaches to viewing this topic; possible patterns (monophasic and polyphasic ones) that one might choose to consider following – each with certain advantages and disadvantages is the first approach. Another perspective on this is considering possible underlying basis to each person’s patterns whether it be effects of genetics on the sleep pattern where it has been shown that there are genetic influences on sleep patterns in twins, environmental factors that might cause similarities between adults and parents’ sleep patterns[1], or effects of different physiological abnormalities/disorders like ADHD, chronic insomnia or pain[2] on sleep patterns. The second possible interpretation when talking about sleep patterns is a single sleep’s patterns or sleep cycle patterns which includes the patterns of REM and Non-REM sleep. Here a special subtopic is dreaming. Dreaming is one thing that scientists have yet to completely understand the purpose of yet there are a lot of different theories to be discussed regarding this topic. The final possible interpretation is one regarding brainwave patterns during sleep. The brain’s electrical activity differs greatly throughout a sleep and when being contrasted with a wakeful state. The biological underlying origins behind that are interesting to consider. In addition, the contrast between those patterns and ones involved in different states of consciousness like hypnosis and meditation and what makes each state unique are topic that has been triggering a lot of interest lately.

1 Sleep-Wake Patterns

An Experience with Biphasic and a Form of Polyphasic Sleep
An interview with Will Xiao which includes a discussion of his experience attempting different
sleeping patterns for a period of 1-2 months and feedback on the experience.[8]

Many subtopics can go under the sleep-wake patterns topic. In particular; discussion of different sleep patterns like monophasic: one long core sleep, approximately 7 hours, per day, biphasic: one core sleep and a 20 minute REM nap in addition to different polyphasicpatterns which represent over two periods of sleep with different numbers of cycles/naps.
The sleep-wake pattern influences and is influenced by many things including exogenous factors exemplified by environment/social factors, endogenous factors including physiological and psychological ones [3], in addition medical or psychological conditions. Another topic that falls under sleep-wake patterns is the effects of those patterns on the brain and the causes behind the patterns.

1.1 Monophasic, Biphasic and Polyphasic Sleep

Polyphasic Sleep Patterns
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This figure illustrates different sleeping patterns. Each pie chart
represents 24 hours and with a certain number of periods of sleep and their
distribution over the 24 hours.[23]

Polyphasic sleep patterns may be adopted to spend less time on sleep yet get the benefits of sleep along with the rest and memory consolidation from it. Furthermore, it has been shown that it is more efficient for some mammals to adopt a polyphasic sleep pattern. [4] In a study examining the sleep patterns of different mammals with different sizes and body masses, a correlation was illustrated between the number of sleep periods in the day and the size of the animal; the smaller the animal, the more sleep periods that it undergoes. The study also showed that smaller animals have a shorter sleep cycle allowing for more cycles in a short period of sleep [4].
The correlation discussed may reflect that animals with smaller bodies would need food more frequently, due to their inability to store a big amount of nutrition in their body and therefore would need to venture for food more often rendering them unable to afford to sleep for too long [4].
Furthermore, when considering polyphasic sleep for humans, people with jobs requiring an alternate sleep pattern might have no choice but to dopt a polyphasic pattern. [5] According to a study done with workers that tend to have a load extending to night shifts forcing them to adopt a polyphasic pattern, it was shown that the total sleep time reduced when volunteers were put on a schedule of 2 hours of activity, 4 hours of rest (sleep included) through the 24 hours. [5] The time of sleep in the 4 hour rest periods increased as the day went on. Good levels of attention and performance were observed despite overall sleep reduction. [5]
A monophasic sleeping pattern, on the other hand, is said to deliver the benefits of sleep more efficiently. [4]

1.2 Effects of Different Patterns on the Brain

An instance of the negative effects that are possible due to bad sleeping patterns is exemplified in a study where it has been shown that there’s a correlation between adolescents that exhibit sleep duration that is less than 7 hours or higher than 9 hours and a decreased mental health status in Japan. [1]
Overall though, the focus of this section and the main problems that arise from a bad sleep pattern can be found in the Sleep Deprivation page.
Otherwise, when looking at non-negative effects of patterns, for the most part, a sleep pattern depends on one’s needs and their schedule. [5] [8] The body can adopt to a new sleeping pattern in a matter of 3-10 days. [6]

1.2a Poor Sleep and Psychiatric Symptoms

A study was conducted with eight to nine year old children were a correlation was found between children with severe sleep problems and the chance that they would encounter a psychiatric disturbance. [9] A correlation between emotional and behavioural problems in addition to school attention with severe sleep problems was also observed in the study. [9]

1.3 Reasons Behind an Individual's Particular Pattterns

In general, there are three main factors with an influence on sleep patterns; exogenous factors, endogenous factors (2012 rats) and medical/psychological conditions.
Many disorders which affect sleep have both exogenous and endogenous causes. Those disorders can affect a person’s sleep pattern/quality of sleep.
A study examining 3,810 adult Austrailian twin pairs with ages varying from 17-88 years old showed that genetic variances were the reason behind 40% of the differences in sleep patterns between the twins. Environmental changes accounted for as much as 30% of the variance while the rest was attributed to the general, stable, environment of the twins. [10]

1.3a Exogenous Factors

Exogenous factors can include a variety of things from environmental to social factors to much more. [3] According to a study conducting comparing sleep patterns between parents and their adolescent children, it was shown that there are similarities in the sleeping patterns between the two which might suggest a genetic basis for sleeping patterns. [1] The study shows that there’s a specially strong correlation between a mother’s poor sleep habits and her parenting style which in turn is shown to have a correlation to the adolescent children’s psychological functioning later on in life. [1]

1.3b Endogenous Influences

Endogenous influences include physiological, psychological [3] and genetic influences. When discussing the genetics, there are many pieces of evidence indicating a correlation between sleep patterns and genes. Sleep disturbances have recently been found to have genetic underlying factors. The sleep-wake cycle has been shown to depend on a genetic transcription feedback loop. [11] In addition, Narcolepsy/cataplexy have been associated with HLA DQB1*0602 and a T-cell receptor. [11]
When it comes to the physiological influences, the circadian clock and sleep-wake homeostat [3] are two mechanisms that work together to regulate the sleep-wake pattern in a day. [3]

1.3c Effects of Medical and Psychological Conditions on Patterns

There are many disorders that directly or indirectly have a big effect on a person’s sleeping patterns. Insomnia is one of the disorders directly related to sleep patterns [12] Though insomnia is mainly characterized by the variability of sleep between the nights, a study which examined the sleep diary of 106 insomniacs that sleep patterns can be classified into 3 main categories making some of the insomniacs’ patterns relatively predictable. [12]
Another study examining the sleeping patterns of patients with chronic pain against ones without in the day and night suggests that there’s a correlation between chronic pain and longer daytime sleep. [2] There has also been a relation between ADHD and sleep disorders like sleep apnea and others. [13]

2 A Single Night's Sleep Patterns

2.1 Sleep Stages: REM and Non-REM Sleep

The sleep cycle is comprised mainly of two different, very distinct, states – REM (Rapid Eye Movement) and NREM (Non-Rapid Eye Movement). [4] In a single night, the brain alternates between the two creating cycles with varying lengths between mammals going from 6 minutes in chinchillas to 90 minutes in humans. [4] In adults, a cycle always starts with an episode of NREM. [4] In addition, each stage is characterized with a different brainwave, shown in the figure titled Sleep Stages.

Sleep Stages
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An adult's monophasic sleep cycles' pattern.[24]

2.1a Dream Theories

Dreams have been studied over the centuries in many different ways in hopes of understanding their purpose. Many correlations have been found with no real proven purpose to dreams. Some correlations include a study which has shown a correlation between the level of intimacy in a relationship and sharing dreams. [14] For the longest time, dreams; their purpose and interpretation, managed to remain a mysterious topic. [15] With the discovery of REM sleep, some neuroscience was discovered to support/disprove some of the previously proposed theories. Unfortunately though, we have yet to discover the scientific backings to allow us to fully interpret their purpose.
Nonetheless, there have been many compelling theories regarding dreams. Three fairly plausible ones are discussed below.
The first theory is one proposing that the purpose of dreams is to train for future events. Dreams provide an environment that allow the brain to simulate a real world environment in order to offer a way for the brain to acquire training in the case where the human being is put in a similar situation as the brain. [15]
Another interesting theory to consider is one that is associated with learning. The theory suggests that dreams are a way for the brain to "get rid of noise" and therefore facilitate learning. [16] If while we're learning, we go down a path that would not lead you to the solution/does not necessarily represent the right interpretation of the problem, dreams are a way for the brain to rid itself from the wrong neuronal connections metaphorically giving us perspective. [16]
The third theory is one that almost gives up on there being a meaning to dreams and attributes dreaming to nothing random neuronal activity.

2.2 Factors Affecting Sleep Cycles

There are many factors that would have an effect on sleep cycles. Two examples of said factors are obesity and age.
According to a study conducted in October 2011 by Citlalli et al., where a mice was fed till it reached a level of obesity and then the mice’s were observed. [17] The slow wave sleep stage in said mice showed a relative increase while the wakefulness of said mice was shown to have been lower than the measurements before feeding the mice. [17] The evidence from this study support the idea of obesity affecting sleep cycles.
Aging is another factor that tends to decrease the period of nighttime sleep as the person’s age progresses. [18]

3 Brainwave Patterns in Wakefulness and Sleep

Brain Waves
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Different brain waves and the circumstances
in which the brain experiences each one. [25]

3.1 Compare and Contrast Sleep Brainwaves and Hypnosis

Hypnosis is a technique with an increasing popularity in the medical field, psychiatry in particular. Though a big part of how hypnosis really works is still a mystery, it has been used in many things from treating disorders, like chronic pain[19] to increasing happiness. [20] Hypnosis is also thought to have the ability of changing a person’s emotions about the past, present and future. [20] Hypnosis is said to, despite popular believe, have brain wave patterns similar to those of the waking state as opposed to the sleep state.[21]

3.2 The Brain State in Meditation and its Effects on the Brain

Meditation has been gaining an increasing amount of attention over the past decades. [22] It has been said to be a way to self-train and improve one’s brain without the need of any exogenous intervention. [22] It has also been shown relieve many symptoms of different illnesses. A study examining the effects of meditation using sleep shows that Long term memory has been shown to be increased in long-term meditators as opposed to individuals with little to no meditation practices. An increase of EEG gamma waves was also observed and was correlated to the amount of meditation a meditator has gone through in their lifetime. [22] Said brain wave, EEG gamma, is then associated with meditation and the brain’s benefits from the practice. [22]

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