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Sleep

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  1. Psychology 001Introduction to PsychologyChristopher Gade, PhDOffice: 621 HeafeyOffice hours: F 3-6 and by apt. Email: gadecj@gmail.com Class WF 7:00-8:30 Heafey 650

  2. Sleep • In the first half of today’s class, we’re going to talk about one type of altered consciousness… sleep. • We’ll first discuss theories about why we sleep. • Biological theories • Evolutionary theories • Cognitive theories • After that, we’ll discuss the different stages of sleep.

  3. The Purpose of Sleep • The Repair and Restoration Theory: • The purpose of sleep is to enable the body to recover from the exertions of the day. • But what needs to recover??? • Muscles • Brain systems • The Randy Gardner exception

  4. The Evolutionary Theory: • Evolution equipped us with a regular pattern of sleeping and waking for the same reason… to conserve fuel and to prevent us from walking into dangers. • What would the purpose of functioning at night be? • Little visual capabilities • Scarce resources and opportunity to find food. • Dangerous predators • A huge amount of energy is required to maintain alertness and to function well in the night environment. • What about today’s world? • Lighting is available • Resources are abundant • Fewer/no predators • Equal amounts of energy are required in both day and night in order to maintain alertness and function well in the night • Does this difference support or refute the evolutionary theory?

  5. Information Consolidation Theory: • Our need for sleep is a result of the brain’s need to consolidate the information obtained throughout the day into memories. • What’s the proof? • High levels of brain activity during sleep • Increased levels of learned responses • Ferret maze experiment • Is there any proof against this theory? • Memories can obviously be established without sleep • Brain activity measures taken during human sleep seem extremely random.


  6. What happens while we sleep? • In the mid 1950’s researchers discovered that during sleep, people display an extremely unusual pattern of behavior several times throughout the night. • REM (rapid eye movement) or paradoxical sleep. • Question: 1950’s??? • From this REM discovery, researchers began observing and defining the different sleep “cycles” that we go thorough.

  7. Measures of Sleep • EEG (electroencephalograph) • Video recordings • Intermittent waking • fMRI • Polysomnograph

  8. Awake Sleep stages 1 2 3 REM 4 0 1 2 3 4 5 6 7 Hours of sleep The Stages of Sleep

  9. Stage 1 • brain waves patterns that closely resemble waking patterns. • Attentive to outside stimuli and can easily be woken. • Will report still being awake when woken in this stage. • Later replaced by REM sleep after the first sleep cycle of the night.

  10. Stage 2 • Brain waves begin emitting “sleep spindles”. These spindles are random bursts of high amplitude EEG waves. There are also “K complexes” found in this stage of sleep. • People woken in this stage report having been asleep. • Dreams can also occur in this stage, but they were (are?) considered less rare. • This stage makes up the majority of our sleep after the first two sleep cycles that we go through in a night.

  11. Stage 3 • This stage is represented by very slow and erratic brain waves. • Believed to have some form of recuperative effect on the body. • Dreams???

  12. Stage 4 • The deepest level of sleep that we encounter. It is represented by long, slow waves on EEG measures. • Very difficult to wake people in this stage. • The stage of sleep that a lot of little children are in while they sleep walk. • Occurs only in the first (or first two) cycle(s) of sleep. • Considered THE recuperative stage of sleep for our bodies.

  13. Stage 5 (REM) • AKA paradoxical sleep • The majority of our body is paralyzed during this stage. Our eyes are highly active. • REM sleep and stage 2 sleep are the two most common stages of sleep after we experience our first two sleep cycles. • Neural activity resembles a waking state during REM sleep. • Associated with memory consolidation and emotion regulation (new studies have contested this idea). • Dreams were originally believed to come only from this stage. • Waking experiments

  14. Added Notes: • These sleep cycles and theories of sleep do not depict an exact replication of everyone’s sleep patterns. • Each individual’s sleep patters vary from the population as a whole, and their sleep need vary as well (some of us need a lot, some of us need a little). • Various sleep abnormalities have a strong impact on the sleep patterns of a number of individuals in the population at some point in time during their lives. • Read up on sleep abnormalities and about different causes for our becoming “tired” in the text.

  15. Now we’re going to discuss… • Dreams!

  16. What can we discuss about dreams? • The meaning of dreams • The purpose of dreaming (from a more modern perspective) • The content of dreams (read about this one in your text)

  17. Freud • “Dreams are a window to our unconscious thoughts, motivations, and desires.” • Freud believed that dreams needed to be broken down into two distinct types of content. • Manifest content – the information in our dreams that appear on the surface (e.g. the story, the people, and the places in our dreams) • Latent content – the hidden themes and symbols (which tell us about the unconscious thoughts, motivations, and desires) that can be abstracted from the manifest content of the dream

  18. Freud (cont.) • Freud also argued that some manifest content in our dreams actually had no latent content in it. • “Sometimes a cigar is just a cigar.” • What is the significance of this statement?

  19. Cognitive Theory (Activation Synthesis Theory) • The prominent theory in our day about what is going on during our dreams. • While we sleep, our brain is producing large numbers of random neural firings. • Our primary cortex (frontal lobe) attempts to make sense of this information. • We create a vivid and relevant story from this. • Dreams appears meaningful because the majority of our neural links are from our prevalent thoughts and common experiences. Thus, we’re more likely to have dreams about things we know.

  20. The Purpose of Dreaming • What can our dreaming actually do? • Allow us to generate insights into problems that we are faced with • Restore/retrace/establish neural connections • Act out fantasies/obstacles in a safe manner

  21. What insights can our dreams reveal to us? • Elias Howe • Dreamt that he was about to be eaten by cannibals • Was taken back by the spears that the cannibals held, which had a hole at the tip • Used this design to invent the needle • Dmitri Mendeleyev (1869) • Elemental table was thought up through a dream

  22. What does this tell us? • Dreams might actually be used as a tool to help us solve problems that we are faced with every day. • Question: How many of you have experienced a math problem, visual-spatial task, or major life question that was impossible to achieve the day it was presented to you, but it became easy when you attempted to overcome the obstacle the next day? • But is this just the result of an illusionary correlation? • Question: How many of you have experienced a math problem, visual-spatial task, or major life question that was impossible to achieve the day it was presented to you, and it was still impossible to overcome the next day?

  23. Side note: • It is important to note that the problems solved in these examples were problems that the figures had already been struggling with. These were not merely moments of random insight about unknown topics. • What can that tell us? • Maybe our brains are just working through the stuff that we already know a lot about during our sleep.

  24. Restore/Retrace/Establish Neural Connection Theory (same as Information Consolidation Theory) • During sleep, almost every part of our brain is activated at some point in time. • Studies have shown that specific brain areas in animals that have been overly active during the day, display higher activity during dreaming. • Ferret maze example revisited • Research has also shown that response time at newly learned tasks, as well as processing speed, is greatly increased after just one day’s sleep.

  25. Problems with the RRE (IC) Theory • We don’t have sophisticated enough tools, and we don’t know enough about the brain to determine with certainty if the firing of neurons during sleep are random, or if they are truly restoring, retracing, and establishing new neural connections. • Studies have shown that our lack of sleep doesn’t have a direct impact on REM sleep. In fact, the percentage of REM sleep we get only increases when we get an abundant amount of sleep.

  26. One final possibility... • Sleep might just have developed because there’s nothing to do at night. • Dreams might actually just be something that developed through evolution as a result of our need to move our eyes at some point in time during the night. • Computer example (from the text)

  27. And then… • Next lecture we’re going to address other forms of consciousness. • So until then, keep studying…