sleep & dreams

sleep:

• state of consciousness

  • the diff levels of awareness & responsiveness to int. & ext. stimuli

  • most psychologists define consciousness as our subjective awareness of ourselves & our envmnt

  • wakefulness

  • sleeping & dreaming

  • altered states of consciousness

• rhythm of sleep

  • circadium rhythm

    • 24 hr cycle including sleep & wakefulness

  • controlled by hypothalamus

    • receives input from eyes & especially sensitive to light & dark cycles of day & night

• one sleep cycle

  • shown on hypnogram graphs

• stages 1-3 of sleep = “quiet sleep”

  • stage 1

    • j drifting to sleep

    • may experience fantastic images &/or auditory hallucinations (hypnagogic sensations)

    • mix of alpha & theta waves

  • stage 2

    • more relaxed

    • clearly asleep

    • sleep spindles = short bursts of brain activity

  • stage 3

    • deepest sleep

    • hard to wake from

    • only occurs during first few sleep cycles of night

    • large delta waves

• REM sleep = paradoxical sleep

  • rapid eye mvmnt

  • brain is almost as active as being awake but body is physically paralyzed

  • dreams

• sleep deprivation

  • teens need 8-10 hrs of sleep

  • there is no making up on sleep (naps don’t count)

  • lots of neg effects

  • REM rebound = incr in sleep duration & intensity

  • jet lag = maladjustment to circadian rhythms resulting from traveling through several time zones in a short span of time

  • shift work = work scheduled during swing shift (4pm-12am) or night shift (12am-8am)

• sleep theories

  • sleep protects = sleeping in darkness when predators loom kept our ancestors out of harm’s way

  • sleep recuperates = sleep helps restore & repair brain & body tissue

  • sleep helps remembering = sleep stores & rebuilds fading mems; memory consolidation

  • sleep & growth = pituitary gland releases growth hormones

  • restoration of resources = brain & body recover & replenish various physical & mental resources during sleep

• sleep disorders

  • insomnia = difficulty falling asleep or staying asleep

  • narcolepsy = overpowering urge to fall asleep that may occur while talking or standing up; sleep attacks lasting abt 5 mins or less

  • REM behavior disorder = muscles are not paralyzed as they should be; seen more often in middle age/elderly men & sometimes linked w/ parkinson’s disease

  • sleep apnea = failure to breathe when asleep

  • sleep walking = aka somnambulism

dreams:

• dream theories

  • wish fulfillment

    • sigmund freud

    • dreams provide a safety value to discharge unconscious wants & desires

    • manifest content = remembered storyline of dream

    • latent content = underlying meaning of dream

  • information processing

    • dreams may help to sift, sort, & fix day’s experiences in our mems

  • physiological function

    • dreams provide sleeping brain w/ periodic stimulation to develop & preserve neural pathways

    • neural networks of newborns are fast developing & therefore need more sleep

  • activation-synthesis theory

    • suggests that brain engages in a lot of random neural activity

    • dreams make sense of random activity bc brain doesn’t like randomness

    • dreams are the brain’s interpretations of its own activity & therefore mean nothing

  • cognitive development

    • some researchers argue that we dream as a part of brain maturation & cognitive development

consolidation theory

• consolidation = stabilization & strengthening of mems over time

• non-REM sleep

  • key for consolidating declarative mems (facts & events) during slow-wave sleep

• REM sleep

  • important for consolidating emotional & procedural mems (skills & habits)

• timing

  • sleep shortly after learning enhances memory consolidation

psychoactive drugs

• blood-brain barrier = a border of blood vessels in the brain that don’t allow the blood of the peripheral nervous system to have an effect on the central nervous system

• psychoactive drugs = chemical substances that alter perception and mood (effect consciousness)

• agonist vs antagonist

  • agonist = mimics neurotransmitter activity (morphine)

  • antagonist = blocks neurotransmitter activity (botox)

• tolerance = effects of a psychoactive drug lessens with repeated exposure

• addiction

  • physical = physical condition caused by chronic use of a tolerance-forming drug in which abrupt withdrawal causes unpleasant physical symptoms

  • a state that involves emotional-motivational withdrawal symptoms upon cessation of drug use

• withdrawal

  • physical symptoms = fatigue, headaches, tremors, sweating, vomiting, & many other varying symptoms

  • psychological symptoms = dysphoria, depression, anxiety, agitation, anhedonia

sensation

• sensation = the process of constructing mental representations of the external world by detecting physical stimulus & converting it into neural signals

• vs perception = when we select, organize, & interpret sensations

• bottom-up processing = analysis of the stimulus begins w/ the sense receptors & works up to the level of the brain & mind (ex: which flag is american flag)

• top-down processing = info processing guided by high level mental processes as we construct perceptions drawing on our experience & expectations (being able to read a sentence despite letters missing)

• transduction = the process by which sensory info is converted into neural signals that the brain can interpret & is crucial for how we perceive & interact w/ the world around us

• absolute threshold = minimum stimulation needed to detect a particular stimulus 50% of the time

• difference threshold = minimum difference between two stimuli required for detection 50% of the time, also called just noticeable difference (JND)

• weber’s law = jnd is proportional to intensity of stimulus

• sensory adaptation = diminshed sensitivity as a consequence of constant stimulation

• sensory interaction = one sense affects the perception of another (taste & smell)

• synesthesia = one sensory stimulation stimulates an automatic & involuntary experiences in another sensory pathway

vision

• optic/visual nerve = bundle of nerve fibers that transmits visual info from retina to brain

• primary function is to bring message from eye to brain

• sensation —> perception once enters brain

• wavelength = distance from one peak of one wave to the peak of the next

• intensity of color = how high each wave is

• amplitude = how high each wave is

• nearsightedness = can see near better but not far

• farsightedness = can see far better but not near

• retina = light-sensitive inner surface of eye & contains rods & cones

• rods = sensitive to light

• cones = color & fine detail

• feature detectors = nerve cells in the visual cortex that respond to specific features (edges, angles, length, mvmnt)

• visual info processing = processing several aspects of the stimulus simultaneously = parallel processing

• monochromatism = grey-scale

• dichromatism = a person is missing either a red or green cone

• trichromatic theory = rbg cones

• opponent process theory = four primary colors opposed in pairs of red-green, blue-yellow, and black-white

• afterimages = supports opponent process theory

• prosopagnosia = ppl can’t recognize the faces of friends and family, and even their own face sometimes

• blindsight = response to visual stimuli w/o conscious awareness of seeing

chemical senses

• gustation/taste = a chemical sense bc a substance is what is detected (not j energy like in sight & hearing)

• super-tasters = more taste buds

• medium tasters = 15-35 taste buds

• non-tasters = 15 or less taste buds

• sweet = donut

• sour = lemon

• salty = salt

• bitter = coffee

• umami = meat

• oleogustus = oils

• astringent = cranberries

• olfaction/smell = relayed directly to brain region associated w/ mems & emotional processes

• sensory interaction = when one sense affects another sense

• pheromones = chem signals that provide info to members of the same species & marks territories