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Sleeping and Dreaming

Sleeping and Dreaming. By: Manpreet Basi MD 1 Case Study 340. Electroencephalogram (EEG):. Electrodes placed on the scalp to provide a gross record of the electrical activity of the brain.

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Sleeping and Dreaming

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  1. Sleeping and Dreaming By: Manpreet Basi MD 1 Case Study 340

  2. Electroencephalogram (EEG): • Electrodes placed on the scalp to provide a gross record of the electrical activity of the brain

  3. Scientists use EEG to measure electrical brain activity during the five stages of sleep. When you fall asleep, you pass through stages 1 to 4 (the deepest level of sleep) as your brain becomes less active. You then go through the stages in reverse before 5 to 15 minutes of stage 5: rapid eye movement (REM) sleep. During REM sleep, your eyes dart about, your brain is frantically active and you dream. The whole cycle lasts about 90 minutes and repeats throughout the night.

  4. EEG Waves of Wakefulness: • Awake, but Non-Attentive – Large, Regular Alpha waves • Awake and Attentive – Low amplitude Fast Irregular Beta waves

  5. Stages of Sleep: • Sleep stage 1 – brief transition stage when first falling asleep • Stages 2 through 4 (slow-wave sleep) - successively deeper stages of sleep • Characterized by an increasing percentage of slow, irregular, high-amplitude delta waves

  6. Stages of Sleep: • Upon reaching stage 4 and after about 80 to 100 minutes of total sleep time, sleep lightens and returns to stages 3 and 2 • REM sleep emerges, characterized by EEG patterns that resemble beta waves of alert wakefulness • muscles most relaxed • rapid eye movements occur • dreams occur • Four or five sleep cycles occur in a typical night’s sleep - less time is spent in slow-wave, more is spent in REM

  7. Functions of Sleep: • Restoration Theory – Body wears out during the day and sleep is necessary to put it back in shape • Preservation and Protection Theory - To preserve energy and protect during the time of day when there is little value and considerable danger

  8. Circadian rhythm: • Any rhythmic change that continues at close to a 24-hour cycle in the absence of 24-hour cues: • Body Temperature • Cortisol Secretion • Sleep and Wakefulness • In the absence of time cues, the cycle period will become somewhat longer than 24 hours

  9. Sleep Deprivation: • Has little effect on performance of tasks requiring physical skill or intellectual judgment • Hurts performance on simple, boring tasks more than challenging ones • Long periods of sleeplessness can cause paranoia and hallucinations at the time, but occasional sleep deprivation doesn't do any long-term damage. • Robert McDonald broke the world record in 1988 when he stayed awake for over 18 days.

  10. Individual Differences in Sleep Drive: • Some individuals need more and some less than the typical 8 hours per night • Nonsomniacs - sleep less than most people and do not feel tired during the day • Insomniacs - people that have a normal desire for sleep, but are unable to and feel tired during the day

  11. Sleep Disorders: • Somnambulism - Sleepwalking • Nightmares - frightening dreams that wake a sleeper from REM • Night terrors - sudden awakening from sleep and intense fear accompanied by physiological reactions (e.g., rapid heart rate, sweating) that occur during slow-wave sleep • Narcolepsy - overpowering urge to fall asleep that may occur while talking or standing up • Sleep apnea - failure to breathe when asleep

  12. How much sleep is needed: • As a person grows older, less sleep is needed. For example a baby needs 16hrs of sleep where as an adult needs 7 hrs of sleep.

  13. Dreams and REM Sleep: • Everyone dreams several times a night • True dream - vivid, detailed dreams consisting of sensory and motor sensations experienced during REM • Sleep thought - lacks vivid sensory and motor sensations, is more similar to daytime thinking, and occurs during slow-wave sleep

  14. Why do we dream: • Researches till this day are not sure why. Some think it is a key to our subconscious or their purpose may be to keep us asleep - the brain's natural entertainer, or it is a way for our brain to be deleting unnecessary information and retaining important information to be stored in our memory.

  15. Brain Mechanisms Controlling Sleep: • Sleep is promoted by a complex set of neural and chemical mechanisms • Daily rhythm of sleep and awakening • Suprachiasmatic nucleus of the Hypothalamus • Pineal gland’s secretion of Melatonin • Slow-wave sleep • Raphe nuclei of the medulla and Pons and the secretion of Serotonin • REM sleep • Neurons of the Pons

  16. Thank you

  17. http://library.wellcome.ac.uk/doc_WTX042113.html • http://psychcentral.com/disorders/sleep/rem.htm

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