1/26/2016
Our Consciousness Varies in:
Consciousness:
Awareness of one’s own mental activity (sensations, feelings
& thoughts) and of the external world
Not just 1 type of consciousness, but a “continuum” of
different levels, from extreme alertness to the deepest coma.
Biorhythms
• Regular, periodic fluctuations in biological
& psychological functioning
• Most common: circadian rhythms - 24 hr
cycles
• Regulated by biological clock in the
suprachiasmatic nucleus (SCN) of
hypothalamus (Concept Organizer 5.1)
• This clock is set/reset by the day/night
cycle – mostly by morning light
• http://www.youtube.com/watch?v=aF24ZmPwzb0
Other Circadian Rhythm Problems
• Shift work where work hours conflict with built-in
biological rhythms
• Travel across time zones – biological clock out of
synch with new location
• SCN adjusts to later schedules (moving to a later
shift or traveling to a later time zone) better than
an earlier schedule
• Morning light of new time zone re-sets SCN. Must
control light exposure to adjust to shiftwork.
• Focus (external vs internal; what we have
selected to attend to)
• Inattentional “blindness” (or deafness) – with focused
attention on one thing we may be blind to or unaware of
other input
• Level of awareness required by different
tasks (controlled vs automatic processes)
Suprachiasmatic Nucleus (SCN)
The clock tells the Pineal
Gland when to secrete
melatonin to make us
sleepy.
Most adults – 10 pm
Teens – 1 am
BUT: our modern day
lights, computer
screens, TVs, and even
glowing LED displays
can confuse the clock
into thinking it is not yet
night time.
Seasonal Affective Disorder (SAD) or
Winter Depression
https://www.youtube.com/watch?v=lld7lFZm-m0
Note: 1st 6
symptoms
resemble what
we see in
animals
preparing to
hibernate –
perhaps SAD
was a functional
way to cope
with winter in
pour ancient past
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1/26/2016
SAD associated with shorter days
Seasonal Affective Disorder
• http://www.webmd.com/depression/video/season
al-affective-disorder-one-womans-struggle
Sleep Lab or
Sleep Clinic
• Monitor:
• EEG (brain waves)
• EOG (eye
movements)
• EMG (muscle
tension)
Sleep
EEG
These 2
deepest stages
are often
lumped
together into a
single stage.
“slow waves”
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1/26/2016
A Typical Night’s Sleep
2 Main Types of Sleep
• NREM (about 80% of night)
• REM or Dream Sleep (20% of night)
Characteristics of
NREM Sleep
• gradual decrease in movements,
breathing, heart rate
• slow, rhythmical brain waves (“delta
waves”)
• hard to wake up
• If awakened you’re likely to say you
were thinking. Only rarely (10%) do you
dream in non–REM.
NREM Sleep “Disorders”
• Tend to run in families
• Very common in kids. Most outgrow them- only a
few adults continue to experience some episodes of
NREM disorders.
• Sleep-walking (17% of kids (peaking at 8-12 yrs), 4%
of adults)
• Night terrors (3% of kids, mostly < 6 yrs)
• Bed-wetting (enuresis)
REM Sleep
• very active brain waves similar to waking
• total loss of tone in most muscles
• rapid jerky eye movements (REMs)
• breathing, heart rate unpredictable
• 80-90% chance of vivid dream report
• erections; vaginal lubrication; regardless
of dream content
REM Sleep Disorders
• Much more rare than NREM problems
• Narcolepsy - REM sleep “attacks” with cataplexy,
muscle paralysis, & hypnagogic hallucinations. Often
triggered by emotion.
• Animal Model of narcolepsy allows research
Several meds can decrease sleep attacks
of narcolepsy:
-stimulants like Ritalin or amphetamine
-somewhat safer Provigil
- or by deepening sleep at night with Xyrem
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1/26/2016
REM Behavior Disorder
• REM behavior disorder - failure of the usual
muscle paralysis mechanism of REM so the person
can move during dreaming
• Unlike narcolepsy, REM behavior disorder usually
occurs in older individuals
• May be associated brain damage/neurological disease
like Parkinson’s disease
• May be triggered by drug use in some
Other Sleep Problems
• Insomnia (over 60 varieties/causes)
• OTC sleeping pills contain antihistamine (diphenhydramine)
• Prescription
• Benzodiazepines- (Xanax, Dalmane, Restoril)
• Non-benzodiazepines (Ambien, Lunesta, Sonata,)
• Over-the-counter – antihistamines
• Sleep Apnea
• CPAP
• Mouthpiece that adjusts jaw position
• Tonsillectomy in kids
• Treatment – medications that decrease REM
Effect of sleep deprivation
on brain activation (math)
Insufficient Sleep Associated With:
• Drowsiness; unintended sleep
• Increased irritability, anxiety, depression
• Decreased socialization & sense of humor
• Decreased cognitive & athletic performance
• Decreased concentration, memory, problem-solving,
creativity, decision-making
• Decreased quality of work & productivity
• Decreased health
• Driving sleepy is as dangerous as driving drunk!! 1 in
6 single driver fatal crashes is due to falling asleep at
the wheel!
Theories Why We Sleep
Norm
al
Sleep
Dep.
Adaptation/Protection Theory
Cross-species Comparisons of Daily Hours of Sleep
• Repair/Restore Theory: sleep allows the body to repair
& replenish itself . During non–REM sleep growth
hormone is secreted, the immune system is more
active, and energy reserves are restored
• Adaptation/ Protection Theory: sleep evolved because
it conserved energy at a time that you couldn’t hunt
for food & helped avoid harm during the more
dangerous time of day, thus had survival value.
• But do these theories fit those that sleep the most
(fetuses & infants)?
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1/26/2016
Both Total Sleep & REM Sleep Over Lifespan Are
Longest During Early Development
• Growth/Development Theory – Sleep (especially
NREM) is for growth & development of brain
• Learning/Memory Theory – Sleep (especially REM)
is needed for memory storage & maintenance
Sleep theories are not mutually exclusive – there’s
data to support all of them
Total Sleep Over Lifespan
Alternative Theories of
REM Sleep Function
• Psychoanalytic/Freudian : dreams are a safe outlet for
unconscious impulses or wish fulfillment
• Biological/Activation synthesis theory: dreams are the
brain’s attempt to make sense of the random
activation of brain cells during sleep
• REM sleep provides necessary activation of brain neurons
during sleep
• Cognitive - REM sleep is another informationprocessing time, helping us organize and interpret
waking thoughts and experiences. Most dreams are
about everyday events.
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