Apr 3 Monday Rhythms, Sleep, Dreaming

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Apr 3 MondayRhythms, Sleep, Dreaming
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• 4. REM sleep - Rapid Eye Movement (REM)
• EEG activation due to increase in firing rates of
  neurons in reticular activating system of
  brainstem, thalamus, and limbic and paralimbic
  areas of cortex
• But prefrontal areas of cortex (executive control
  centers) are not very activated
• Active thalamus provides high sensory input to
  dreams
• High visual imagery like visual hallucinations
  cholinergic stimulation. During waking,
  cholinergic system less in control than are NE
  and SE
• Dreams show emotional (limbic) and instinctual
  drive (paralimbic) content
• Dreams are illogical, lack continuity, and
  bizarre (no executive control/ thought
  prefrontal cortex not active)

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Formal psychological features of dreaming are
determined by the specific regional activation
patterns and neurochemistry during sleep. Hobson
and Pace-Schott, 2002
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• Wakefulness
• Several brain arousal systems facilitate
  wakefulness.
• Brainstem reticular activating system
  structures in core of pons and medulla that
  project to hypothalamus and basal forebrain
  inhibit sleep control centers and activate basal
  forebrain
• Hypothalamic arousal systems

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Brainstem reticular activating system is at core
of pons and medulla.
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• 2. The Hypothalamic Arousal Systems
• a. Posterior hypothalamus uses Serotonin,
  Norepinephrine, and Histamine to modulate
  multiple areas and promote wakefulness in
  forebrain
• b. Lateral hypothalamus uses Orexin to
  stabilize wake state and prevent switching from
  wake to sleep at the wrong time
• (Narcoleptics have reduced of Orexin-producing
  neurons and reduced levels of Orexin in CSF)
• During sleep, there is a progressive decrease
  across stages in output from SE, NE, and
  histamine neurons to point of being shut off
  during REM. This leaves the forebrain
  unmodulated by these waking factors and instead
  influenced more by Acetylcholine. This precludes
  waking consciousness.

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• Sleep and Cognition
• 1. Sleep is recuperative reduced energy demands
  allow rest and re-building
• 2. Sleep promotes plasticity
• infants in late fetal development in utero and
  premature infants show almost exclusive REM-like
  activity period of rapid brain growth and
  synaptogenesis
• (This does not mean that REM plays the same role
  in adults)
• in 1st year of life, infants spend higher
  proportion of time in REM stage (around age 10,
  stabilizes at adult level)

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• Sleep and Cognition
• 1. Sleep is recuperative reduced energy demands
• 2. Sleep promotes plasticity
• sleep enhances experimentally-induced cortical
  plasticity
• Monocular deprivation produces increase in of
  neurons in primary visual cortex that respond to
  information from the non-occluded eye more brain
  cells respond to dominant eye
• Block one eye all info through other eye
  brain wires up to better serve the seeing eye
• Sleep enhances this plasticity

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• Sleep and Cognition
• 2. Sleep promotes plasticity
• sleep promotes storage and consolidation of new
  information acquired during prior waking (NREM
  and REM important, perhaps for different types of
  memory).
• Evidence for learning-related neuronal replay
  during sleep same circuits fire as were firing
  during training.
• Ex. You may have experienced
  experience-related hypnogogic hallucination
  replay of videogame playing cant clear head of
  math problems study info., etc

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• Sleep and Cognition
• 2. Sleep promotes plasticity
• sleep deprivation interferes with learning
  deprive the night after training, dont learn
  even after given recovery sleep

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• Sleep Deprivation
• studies depriving Ss for 205 hrs (8.5 days)
• irritability disorientation difficulty
  concentrating occasional hallucination
  variable performance
• But effects are more pronounced in the morning
  than later in day. Performance has been
  measured as indistinguishable from normal on
  several tasks.
• record is 264 hrs (11 days)

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• Sleep Disorders
• Dysfunctions of Sleep Stages or Transitions
• A. Disorders of arousal occur in 10 of
  adults far more common in children occur
  during slow wave sleep (usually stages 3 and 4)
• Sleepwalking (associated disordersSleep
  eating or Nocturnal Eating Syndrome Sleep sex)
  slow wave sleep more common in first half of
  night.
• Night terrors Slow wave sleep
• Bedwetting Slow wave sleep

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• Sleep Disorders
• Dysfunctions of Sleep Stages or Transitions
• A. Disorders of arousal
• B. REM Behavior Disorder organized behavior
  occur where people seem to be acting out dreams
  while appearing to be asleep
• - muscles are not paralyzed during REM as they
  should be
• - usually begins after age 50
• - more common in men
• - sometimes precedes the onset of Parkinsons
  Disease

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II. Disorders of Excessive Drowsiness drowsy
all the time or may have sudden sleep
attacks Narcolepsy sudden sleep attacks that
last 5-30 minutes - can occur anytime during
usual waking period, often about every 90
minutes - usually begins at 15-25 yrs of age and
continues Animal model (dog) genetic
abnormality Humans loss of 90 of neurons for
Orexin (hypocretin) causes abnormal transition
into sleep and REM
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III. Disorders of initiating or maintaining
sleep Insomnia 15-30 of adults includes
many cases that are secondary to stimulant drug
use (caffeine nicotine) or drugs that interfere
with sleep stages (alcohol) or respiratory
disorders Sleep apnea stop breathing for 1-2
minutes, then aroused enough to breathe (or
gasp) Common in obese persons premature infants
(sudden infant death syndrome) For infants -
use a sleep monitor sleep on back (50
reduction) Adults can use a continuous positive
airway machine
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Neurobiology of Stress and Anxiety
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Stress a state of emotional arousal that may
interfere with performance and coping Stress
complex response to environmental demands Stress
a response of the body to a stimulus or stimuli
that alters normal physiological equilibrium
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• Factors that influence how stressful we rate a
  particular situation
• familiarity - less familiar, the more threatened
  you may feel. Ex 1st test vs 2nd traffic in LA
  vs Boston
• controllability - if under our control, less
  stressful. Ex Traffic jam - stress take
  alternative route - just as long but less stress.
• Drive not fly more dangerous, but under our
  control more

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- controllability The Executive Monkey Studies -
2 monkeys - one can press bar to terminate
shock the other cannot. Get identical shocks
for same amount of time - one has control, the
other does not. Yoked control design Monkey
with no control gtgt more stress
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• Factors that influence how stressful we rate a
  particular situation
• predictability - more predictable, less
  stressful.
• Executive Monkey Studies - for one monkey, light
  warns that shock is coming for other, no
  warning.
• More signs of stress in monkey who gets no
  warnings.(Ex. unexpected shots pop quizzes)

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• Factors that influence how stressful we rate a
  particular situation
• predictability
• appraisal of situation - personal interpretation
  of situation
• Individual differences - reactions to flying
  blind dates surgery exams death, fights, Sept
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• Stress is in the eye of the beholder

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Responses to Stress 1. Emotional responses -
anger, annoyance, anxiety, apprehension, grief,
sadness. Strong emotional arousal can interfere
with performance and coping. Optimal arousal
level below or beyond that, performance
impaired. (inverted U) test anxiety
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Responses to Stress 1. Emotional responses 2.
Behavioral responses - involve some type of
coping - healthy or unhealthy.
Striking out at others
venting emotion giving up
indulging oneself - eating shopping
Getting involved.
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Responses to Stress 1. Emotional responses 2.
Behavioral responses 3. Physiological responses
- immediate response may be emotional long term
stress may impact health.