SLEEPRonald Cargill

Psych 275

Why is Sleep Important?

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Our brain releases the hormone cortisol when we are lacking a certain amount of sleep, and treats this deprivation as a stressor. The release of cortisol will damage our immune system, eventually.

When we do not sleep well, our brain functions below its capability, impairing our judgment, and produces slower reaction times.

Certain parts of our brain stem respond to fatigue and diurnal rhythms (our 24 hour cycle) by regulating sleep and wakefulness.

Cerebrospinal fluid that surrounds our brain begins to accumulate SRS proteins (sleep regulatory substances) which induce sleep when the proteins reach a certain concentration level.

The amount of sleep needed per night depends on each individual’s age, health, and sleep patterns. Infants need 16 hours a day, teenagers need 9 hours, and adults function best when they get 7-8 hours of sleep per night (Sweeney, 2009).

Stages of SleepStages 1 – 4 (NREM – Non Rapid Eye Movement)

Stage 1: Light Sleep, muscle contractions can still be initiated and sleeper can be woken up easily.Stage 2: Consists of about 50% of an adult’s sleep cycle, eye movement seizes and activity within the brain decreases.Stage 3: Delta waves, or extremely slow brain waves, begin to appear.Stage 4: Brain activity consists predominantly of delta waves (Sweeney, 2009).

Stages 3 and 4 - deep layers of sleep - if awakened during these stages, the subject is very groggy.

Image retrieved from personal collection

Stages of SleepStage 5 (REM) REM occurs approximately 90 minutes after falling asleep. Accounts for 50% of an infant’s sleep, and 30% of an adult’s. Dreaming occurs during REM The cerebral cortex paralyzes the limbs during this dream state to keep the sleeper from acting

out their dreams. Once REM is completed, the cycle repeats. The longer you sleep, the longer REM stage and

Stages 3 & 4 lengthen (Sweeney, 2009).

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Introduction to Sleep Disorders Each year, 40 million Americans suffer from chronic sleep disorders. 20 million additional Americans suffer from occasional sleep problems.

(National Institute of Neurological Disorders and Stroke)

Next, I will discuss sleep deprivation, and then talk about the four most common sleep disorders. These will include sleep apnea, restless legs syndrome, insomnia, and narcolepsy.

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Sleep Deprivation 26% of people in a survey consisting of 79,625 Americans with sleep problems were more likely

to report symptoms of depression and anxiety along with adverse health problems.

Studies indicate that people who are deprived of sleep for 56 hours, in addition to depression and anxiety symptoms, also reported paranoia.

According to the American Psychological Association, people who are sleep deprived may experienced slowed speech, flattened emotional responses, and apathy (Barnett, 2008).

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Sleep Apnea

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• Sleep apnea patients suffer from a reduction in oxygen to the brain due to a lapse in breathing during sleep. The neurocognitive signs of this reduction in oxygen to the central nervous system include personality alterations, daytime sleepiness, impaired concentration, memory, communication, and learning.

• Studies show that even with patients suffering from acute sleep apnea, the neuronal circuitry in their brain were changed. Animal studies have shown that the lack of oxygen to the brain causes learning and memory impairment and neuronal death (Aviles-Reyes, et al., 2007).

RLS (Restless Legs Syndrome)

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• Affects 12 million Americans – may occur at any age, but most common in the elderly.

• Evidence suggests that RLS is related to a dysfunction in the brain’s basal ganglia circuit that use the neurotransmitter, dopamine. Dopamine helps regulate smooth muscle activity and movement. Disruption in this circuit would result in an uncontrollable urge to move their legs (NINDS).

• The National Institute of Neurological Disorders and Strokes suggests that there is evidence that low levels of iron in the brain may also be the cause of restless legs syndrome.

Insomnia

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• 60 million Americans report having insomnia frequently or for long periods of time. Insomnia increases with age and affects 40% of women and 30% of men (NINDS).

• Research has found that people who suffer insomnia possibly have 25-30% less gamma-aminobutyric acid than people without insomnia. Gamma-aminobutyric acid, or GABA, is a neurotransmitter that helps regions in the brain shut down by reducing electrical activity.

• Without the adequate amounts of GABA, the brain is unable to slow down which makes sleeping extremely difficult. It is inconclusive whether it is the lack of GABA that causes insomnia, or that insomnia causes the reduction in GABA (Mehta, 2008).

Narcolepsy

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• People affected by narcolepsy may experience several sleep “attacks” per day. These attacks may occur at any time of day, including during activities such as driving or even during a conversation.

• Narcolepsy is a neurological disorder that can begin at any age, but usually develops between the ages of 10 and 25 years old.

• The brain peptide, hypocretin, appears to be deficient in most cases concerning narcolepsy with cataplexy (sudden loss of muscle tone that is triggered by emotions). Hypocretin is a neurotransmitter found in the dorsolateral hypothalamus that regulates sleep/wakefulness, arousal, and appetite. A deficiency in this peptide can lead to abnormalities in its function, which can cause narcoleptic symptoms (Peacock & Benca, 2010).

Conclusion If you are curious as to whether you may or may not have a sleeping disorder, click here.

Below is a link to a YouTube video that I found quite interesting regarding a man diagnosed as a Narcoleptic with Cataplexy.

Narcolepsy Video

Below is a 20 minute video, if you are interested, on SHY (Synaptic Homeostasis Hypothesis) presented by Dr. Tononi of University of Wisconsin, Madison.

SHY

Thank you for taking the time to go through my PowerPoint. I hope that I have informed you of some new information on sleep and sleep disorders.

Annotated Bibliography Aviles-Reyes, R., Angelo, M., Villarreal, A., Rios, H., Lazarowski, A., & Ramos, A. (2010). Intermittent Hypoxia During Sleep

Induces Reactive Gliosis and Limited Neuronal Death in Rats: Implications for Sleep Apnea. Journal Of Neurochemistry, 112(4), 854-869.

The information retrieved from this scholarly journal was used to summarize basic knowledge of the sleep disorder, sleep apnea and its effect on the brain.

Barnett, K. J. (2008). The Effects of a Poor Night Sleep on Mood, Cognitive, Autonomic, and Electrophysiological Measures. Journal of Integrative Neuroscience, 7 (3), 405-420.

This information retrieved off this academic journal consists of a study performed regarding sleep deprivation and its cognitive effect on the subjects. Information was retrieved on the EBSCO database.

Brain Basics: Understanding Sleep. National Institute of Neurological Disorders and Stroke, Bethesda, MD. 2007. Web.

This information retrieved off of the National Institute of Neurological Disorders and Stroke website consists of basic statistical information regarding sleep disorders in the United States.

Mehta, A. (2008). Insomnia Tied to Lack of Brain Chemical. The Dana Foundation. Web.

The information retrieved off this website summarizes a possibility that the lack of the neurotransmitter GAMA is responsible for the sleep disorder, insomnia.

Peacock, J., & Benca, R.M. (2010). Narcolepsy: Clinical Features, Co-morbidities & Treatment. Indian Journal of Medical Research, 131 (2), 338-349.

The information retrieved from this article summarizes the condition known as narcolepsy. It also explains the possible causes behind the disorder, hypocretin.

Annotated Bibliography (cont.) Sleep. American Psychological Association, Washington D.C. 2012. Web.

The information derived from the American Psychological Association website was used solely to reference information listed on the Sleep Deprivation slide in this PowerPoint.

Sweeney, Michael S. (2009). Brain: The Complete Mind. National Geographic Society, Washington, D.C. 188-189.

I retrieved the necessary information on the stages of sleep from our textbook, Brain: The Complete Mind. I summarized the information on Stages 1-5, including both Non-Rapid Eye Movement stages and Rapid Eye Movement during our sleep cycle.