Pineal Gland

Why do we spend 1/3 of our lives being unconcious?

Sleep is an automatic process we try to control but probably need to increase.

We get so focused on our tasks and activities, we try to limit the amount of sleep we get. But this mysterious process of sleep is not optional. It’s good for us.

• light therapy
• limbic system
• lowest body temp
• melatonin
• memorable dreaming
• memory consolidation
• N1
• N2
• N3 (delta)
• narcolepsy
• NREM
• oral appliance therapy (OAT)
• paralysis
• pineal body
• pineal gland
• pinealocytes
• rapid eye movements
• REM
• serotonin
• sigma bands or sigma waves
• sleep apnea
• sleep debt
• sleep deprivation
• sleep disorders
• sleep duration
• sleep spindles
• sleep study = polysomnogram
• somnolence
• stages
• sunlight
• threat-simulation theory
• total sleep time
• transducer
• transitions
• trans-meridian distance (west–east)
• tremors
• turbinate surgery
• turbinates
• unconscious wishes
• yawning

 

NOTES

• Limbic System (con’t)
• Pineal Gland
  • Also called
    • pineal body
    • epiphysis cerebri
    • epiphysis
    • third eye
  • Endocrine gland
  • Produces melatonin
    • Derivative of serotonin
    • Affects modulation of wake/sleep
  • Shape of pine cone
    • Size of grain of rice
    • Reddish-gray in color
  • Calcifies as get older
    • “Brain sand”
    • Tumors are rare
  • Composed of:
    • Pinealocytes
      • cell body with 4–6 processes
      • produce & secrete melatonin
    • Interstitial cells
      • between pinealocytes
  • Conjecture
    • Near death experience?
    • Psychedelic experiences?
    • Antidepressants (Prozac)?
    • Cocaine?
  • Transducer
    • Like adrenal medulla
    • Converts sympathetic nervous system to hormones
  • How it works
    • Hypothalamus to spinal cord
      • To superior cervical ganglia
        • To pineal gland
    • Mature by age 2 yrs.
    • Lots of melatonin may inhibit sexual development of children
    • At puberty, melatonin decreases
  • Discovery
    • Aaron Lerner
      • Yale dermatology professor
    • Hoped pineal gland substance would help treat skin diseases
    • Called it melatonin
  • Melatonin
    • Tryptophan—Serotonin–Melatonin
    • Production $ by darkness
    • Inhibited by light
  • Photosensitive cells in retina
    • Detect amount of light
    • Signal SCN
  • Set 24-hr cycle
  • Duction $ by darkness
    • Movement of 1 eye
    • Retina
    • SCN signal PVN
    • Paraventricular nuclei to
    • Signal spinal cord then to
    • Superior cervical ganglia and then to
    • Pineal gland
  • Blood levels of melatonin
    • Undetectable during day
      • rise sharply when dark
    • Longer the night, more melatonin
    • Some effect on sleep
      • Not major regulator
    • If you take melatonin
      • Mild help to elderly insomniacs
    • Shift workers
      • Not as good as phototherapy
    • Jet lag
      • Taken close to target bedtime
      • Best effect when crossing many time zones
• Sleep
  • Stages
    • Awake
    • REM
    • Stage 1
    • Stage 2
    • Stage 3
  • Mammals and birds
    • REM
    • NREM
    • N1
    • N2
    • N3 (delta) = slow wave sleep; deep sleep
  • Historically:
    • Alfred Loomis, 1937
      • EEG; five levels (A to E)
    • Dement & Kleitman, 1953
      • REM sleep plus 4 NREM
    • Now, 3 stages plus REM
      • combined stages 3 and 4
      • Stages based on EEG, eye movements, respiratory, cardiac, and movement events
  • Cycles
    • N1 → N2 → N3 → N2 → REM
    • proportion of REM sleep increases until just before natural awakening
  • In humans (adults)
    • Sleep cycle from 90 to 110 min.
    • 60 minutes for newborns
  • NREM
    • Relatively little dreaming in NREM
    • Stage N1
      • transition from alpha (awake)
        • 8-13 HZ alpha waves
      • To delta waves
        • 4–7 Hz delta waves
      • Somnolence or drowsy sleep
      • Twitches and jerks
      • Hallucinations
      • Lower awareness of external environment
    • Stage N2
      • Less movement, no awareness
      • About 50% of sleep time
      • K-complexes
        • Brief high-voltage peaks
          • roughly every minute
        • often followed by bursts of sleep spindles
        • Suppress cortical arousal
        • Expect to danger signals
        • Aides memory consolidation
      • Sleep Spindles
        • Also called “sigma bands” or “sigma waves“
        • Last half second
        • Sudden bursts
    • Stage N3
      • Deep or slow-wave sleep
        • minimum of 20% delta waves
      • Night terrors
      • Bed wetting
      • Sleepwalking
  • REM
    • Rapid eye movement sleep
    • 20–25% of total sleep time
      • rapid eye movements
      • rapid low-voltage EEG
    • Memorable dreaming
    • Paralysis
  • Sleep timing
    • Controlled by circadian clock
    • Timekeeping, temperature-fluctuating, enzyme-controlling device
    • Adenosine (neurotransmitter)
    • Inhibits wakefulness
    • Increases over the day
    • Sleepiness
    • Causes release of melatonin
    • Gradual decrease in body temp
  • Sleep duration
    • affected by the DEC2 gene
    • mutation of this gene; sleep two hours less than normal people
  • Optimal amount & timing
    • Be asleep
      • 6 hrs before lowest body temp
    • Max level of melatonin
    • Min core body temperature
  • Adequate = not sleepy in daytime
    • Varies with individual
    • Varies with age
    • Child to adult
  • Hours by age
    • Child need more sleep per day
    • Newborn = up to 18 hrs
      • 9 hours a day in REM sleep
      • 1-3 yr olds = 12-15
    • School age = 10 to 11 hrs
    • Adolescents = 9-10 hrs
    • Adults = 7-8
      • More if pregnant
      • Not less is elderly
  • Sleep debt
    • Not getting enough sleep
    • Impacts frontal lobes
    • Findings are mixed
  • Lack of sleep
    • Sign of cardiovascular disease?
  • Too much sleep
    • Sign of depression?
  • Sleep Problems
    • May have:
      • Depression, alcoholism, bipolar
      • 90% of depressed have sleep disorders?
  • Sleep Deprivation
    • Cognitive impairment
    • Memory loss
    • Moral judgment
    • ADHD symptoms
    • Motor impairment
    • Decreased reaction time
    • Less accurate
    • Tremors
    • Aches
    • Symptoms
    • Irritable
    • Yawning
    • Hallucinations
  • Impacts
    • Immune system impairment
    • Heart rate is more variable
    • Risk diabetes & heart attack
    • Decreased temp
  • Sleep Disorders
    • Jet Lag
      • Called desynchronosis
      • Alterations to circadian rhythms
      • Sleep disorder
      • May last several days
      • Figure 1 day per time zone
      • Out of synch w destination time
        • contrary to accustomed rhythms
        • times for eating, sleeping, hormone regulation and body temperature
      • How long to adjust
        • Varies greatly
        • Cross 1-2 time zones no prob.
        • Not linked to length of flight
          • 10 hr flight within time zone okay
            • Europe to southern Africa
            • trans-meridian distance (west–east)
          • 5 hr flight from LA to NY
            • International Date Line
        • Maximum possible disruption is 12 hours plus or minus
      • Symptoms vary
        • Headaches, irritability
        • Fatigue, mild depression
        • Sleep problems
        • Digestive problems (constipation-diarrhea)
      • To minimize effects
        • Before the flight
          • Ask doctor about meds
          • Partially adapt
            • get up an hour earlier
            • light box
        • During flight
          • Travel in smaller segments
          • Overnight midway
          • Set time to destination
            • Sleep-wake
        • After flight
          • Sunlight
          • Eat on schedule
      • Travel west to east is hardest
        • Most people have circadian period a little over 24 hours
        • Easier to stay up later
          • Harder to get up earlier
        • London to LA: 8 hr difference
          • Stay up all night, go bed at 6am
        • LA to London: 8 hr difference
          • Stay up all night, go bed at 2pm
        • Red-eye flight
        • West to east
          • body gets less rest to begin day
      • How fix
        • Gradually adjust start of sleep
          • Adjust over several days
        • Avoid afternoon naps
        • Eat on schedule, avoid carbs
        • Melatonin?
          • Hard to make timing precise
          • Need max level 6 hours into sleep
          • Light hits eyes, secretion stops
          • Impacts circadian
        • Light therapy
          • One day per time zone adjust
          • Start with light, avoid other times
          • Possible but untested
        • Fasting?
          • lack of food overrides light-controlled circadian body clock?
          • no food at all for 16 hours
          • eat nothing on plane; don’t eat until destination’s breakfast time
    • Sleep apnea
      • During sleep
        • Abnormal pauses in breathing (apnea)
        • Abnormal low breathing (hypopnea)
      • Each apnea can last
        • Seconds to minutes
      • 5-30 per hour
      • Sleep Study = polysomnogram
      • Most common in men
        • 2+ times for often
      • Can affect children too
        • excessive daytime sleepiness
        • slower reaction time
        • daytime fatigue
        • vision problems
      • Treatment
        • CPAP machine
          • Continuous Positive Airway Pressure
          • pumps air into throat
        • Turbinate surgery
          • Grind down turbinates in nose
        • Oral Appliance Therapy (OAT)
          • Dental appliance; custom-made mouthpiece to shift lower jaw
    • Narcolepsy
      • Symptoms
        • Excessive sleepiness
        • Fall asleep at inappropriate times
          • Work
          • Driving
        • Cataplexy
          • Sudden muscular weakness when emotional
          • Drop head, weak knees, collapse
          • Slurred speech but normal hearing
      • Often confused with insomnia
        • REM within 5 minutes
        • An hour before normal
      • Possible genetic cause
      • Treat with amphetamines
        • Provigil or Nuvigil
• Dreams
  • Sequence of
    • Images, sensation, emotions
    • Occur involuntary
    • Most common in REM sleep
    • Most vivid in REM
  • Purpose = unknown
  • Duration of second to 20 min.
    • Get longer as night progresses
    • More REM as night progresses
  • 5-minute dream is about 5-minutes of story
    • Don’t compress a day into 5 min.
  • Remember if awakened in REM
  • 3-5 dreams per night
  • About 2 hrs per night
  • Feel out of your control
    • Except lucid self-aware dreams
  • Can provide creative thoughts, problem solutions or inspiration
  • REM has no release of:
    • Norepinephrine, serotonin & histamine
    • All mammals experience REM
      • dolphins experience minimum
      • humans are in the middle
      • opossum and the armadillo most
  • Theories
    • Ancient
      • Fates and gods talking to you
    • Unconscious Mind
      • Sigmund Freud
      • Unconscious wishes
    • Threat-simulation theory
      • Antti Revonsuo
      • Prepare you for real life
    • Activation Theory
      • Hobson & McCarley
      • Random neuron firings