Body Rhythms and Mental States
Consciousness: awareness of oneself and the environment
Biological Rhythms: The Tides of Experience
Biological Rhythm: a periodic, more or less regular fluctuation in a biological system; may or may
not have psychological implications
Biological clock in brains governs waxing and waning of hormone levels, urine volume, blood
pressure, and even the responsiveness of brain cells to stimulation
Entrainment: the synchronization of biological rhythms with external cues, such as fluctuations
in daylight
Endogenous: generated from within rather than by external cues
Circadian Rhythm: a biological rhythm with a period (from peak to peak or trough to trough) of
about 24 hours; from the Latin circa, “about” and dies, “a day”
o Best-known circadian rhythm is the sleep-wake cycle, but there are hundreds of others
that affect physiology and performance
Ex. Body temperature fluctuates about one degree centigrade each day,
peaking, on average, in the late afternoon and hitting a low point, or tough in
the wee hours of the morning
Seasonal rhythms common. Birds migrate south in fall, bears hibernate in winter, and marine
animals become active or inactive depending on bimonthly changes in tides
In humans, female menstrual cycle occurs every 28 days on average
Biological rhythms influence everything from the effectiveness of medicines taken at different
times of day to alertness and performance on job
With better understanding of internal tempos, may be able to design out days to take better
advantage of our bodies’ natural tempos
Circadian Rhythms
Exist in plants, animals, insects, and humans
Reflect adaptation of organisms to many changes associated with rotation of Earth on axis such
as changes in light, air pressure, and temperature
External time cues abound, and people's circadian rhythms become entrained to them,
following strict 24-hour schedule
To identify endogenous rhythms, scientists must isolate volunteers from sunlight, clocks,
environmental sounds, and all other cues to time
o Some have spent weeks or even months alone in caves and salt mines, linked to outside
world by one-way phone line and cable transmitting physiological measurements to
surface
o Now volunteers live in specially designed rooms equipped with stereo systems,
comfortable furniture, and temperature controls
o When participants have been allowed to sleep, eat, and work whenever they wished,
few have lived a “day” that is much shorter or longer than 24 hours. If allowed to take
daytime naps however, most participants live a day that averages about 24.3 hours
Commonly entrained to external time cues
Endogenous rhythm averages around 24.3 hrs
Removed from cues about 10% of people have clocks running slower and 10% running faster Increase in accidents at transition to daylight Saving Time
The Body’s Clock
Suprachiasmatic Nucleus (SCN): an area of the brain containing a biological clock that governs
circadian rhythms
o Located in tiny teardrop-shaped cluster of cells in hypothalamus
o Neural pathways from special receptors in back of eye transmit information to SCN and
allow it to respond to changes in light and dark. SCN then sends out messages that
cause brain and body to adapt to changes
Other clocks exist but SCN regarded as master pacemaker
Melatonin: a hormone, secreted by the pineal gland, that is involved in the regulation of daily
biological (circadian) rhythms
o When sleep in darkened room, melatonin level rises, when wake up to lightened room,
melatonin falls
Melatonin therapy used to treat insomnia and synchronize disturbed sleep-wake cycles of blind
people who lack light perception and whose melatonin production doesn’t cycle normally
When the Clock is Out of Sync
Internal Desynchronization: a state in which biological rhythms are not in phase (synchronized)
with one another
o Often occurs when people take airplane flights across several time zones
o Sleep and wake patterns adjust quickly but temperature and hormone cycles can take
several days
o Jet lag affects energy level, mental skills, and motor coordination
Occurs when worker must adjust to new shift. Efficiency drops, person tired and irritable,
accidents become more likely, sleep and digestive disorders may occur
May become matter of life and death for cops, emergency room personnel, airline pilots, truck
drivers, and operators of nuclear power plants
University of British Columbia research Stanley Coren studied records of all accidental deaths in
the US over a three-year period, found that the spring shift to daylight saving time (and the
minimal sleep loss associated with it) produced short-term increase in likelihood of accidental
death but the fall shift had little effect
Rotating night-shift assignments don’t allow worker’s circadian rhythms do resynchronize, can
help resynchronize by using melatonin or other techniques, not ready however
o Best approach is to avoid shifting as much as possible
Circadian rhythms not perfectly regular in daily life. Can be affected by illness, stress, fatigue,
excitement, exercise, drugs, mealtimes, and ordinary daily experiences. Even diet
Circadian rhythms differ greatly from individual to individual because of genetics
Moods and Long-Term Rhythms
Ecclesiastes “To everything there is a season, and a time for every purpose under the heaven.”
Does the Season Affect Moods?
Some people become depressed during particular seasons, typically winter, when periods of
daylight are short- known as seasonal affective disorder (SAD)
During winter months, SAD patients report feelings of sadness, lethargy, drowsiness, and a
craving for carbs To counter effects of sunless days, physicians and therapists have been treating SAD patients
with phototherapy, having them sit in front of bright fluorescent lights at specific times of the
day, usually early in the morning. Also prescribing antidepressants and other drugs
Approx. 2-3% of Canadian population suffers from SAD, US is less than 1% same with Europe,
Asian is 0-1%
Much more common in women, ratio about 2:1
When people with SAD exposed to either a brief period (about 30 minutes) of bright light after
waking or to light that slowly became brighter, simulating dawn, their symptoms were reduced
Concluded that SAD patients must have some abnormality in the way they produce or respond
to melatonin
One study, SAD patients produced melatonin for about half an hour longer at night in winter
than summer whereas control subjects showed no season pattern
Does the Menstrual Cycle Affect Moods?
First half, increase in estrogen causes lining of uterus to thicken in preparation for possible
pregnancy. Mid-cycle, ovaries release mature egg, or ovum. After, ovarian sac that contained
egg begins to produce progesterone- helps prepare uterine lining to receive egg. Then, if
conception doesn’t occur, estrogen and progesterone levels fall, uterine lining sloughs off as the
menstrual flow and cycle begins again
Question is whether these physical changes are correlated with emotional or intellectual
changes as folklore and tradition would have us believe
Most people think so, physical symptoms (fatigue, headache, irritability, and depression)
associated with the days preceding menstruation came to be thought of as an illness and was
given the label: “premenstrual syndrome” (PMS). Since then, most people have assumed,
uncritically, that many women “suffer” from PMS or its supposedly more extreme and
debilitating version, “premenstrual dysphoric disorder” (PMDD)
What does evidence actually show? Many women have physical symptoms associated with
menstruation, including cramps, breast tenderness, and water retention although women vary
tremendously. Physical symptoms can just make women grumpy or unhappy just as pain can
make men grumpy or unhappy
But emotional symptoms associated with menstruation (notably irritability and depression) are
pretty rare
Just like with SAD patients, more people claim to have symptoms than actually do
In reality, fewer than 5% of all women have such symptoms predictably over their cycles
Consciousness is the awareness of oneself and the environment. Changing states of
consciousness are often associated with biological rhythms- periodic fluctuations in
physiological functioning. These rhythms are typical entrained (synchronized) to external cues,
but many are also endogenous, generated from within even in the absence of time cues.
Circadian fluctuations occur about once a day; other rhythms occur less frequently or more.
When people live in isolation from all time cues, they tend to live a day that is just slightly longer
than 24 hours. Circadian rhythms are governed by a biological “clock” in the Suprachiasmatic
nucleus (SCN) of the hypothalamus. The SCN regulates, and in turn is affected by, the hormone
melatonin, which responds to changes in light and dark and which increases during the dark
hours. When a person’s normal routine changes, the person may experience internal
Desynchronization, in which the usual circadian rhythms are thrown out of phase with one
another. The result may be fatigue, mental inefficiency, and an increased risk of accidents Folklore holds that moods follow long-term biological rhythms. Some people do show a
recurrence of depression every winter, in a pattern that has been labelled seasonal affective
disorder (SAD), but serious seasonal depression is rare. The causes of SAD are not yet clear, but
may involve an abnormality in the secretion of melatonin. Light treatments can be effective
Another long-term rhythm is the menstrual cycle, during which various hormone levels rise and
fall. Well-controlled double-blind studies on “PMS” do not support claims that emotional
symptoms are reliably and universally tied to the menstrual cycle. Overall, women and men do
not differ in the emotional symptoms they report or in the number of mood swings they
experience over the course of a month
Expectations and learning affect how both sexes interpret bodily and emotional changes. Few
people of either sex are likely to undergo dramatic monthly mood swings or personality changes
because of hormones
The Rhythms of Sleep
Christopher Evans “The behaviour patterns involved in sleep are glaringly, almost insanely, at
odds with common sense.”
The Realms of Sleep
Not much was known about changes that occur in brain during sleep until early 1950s in lab of
physiologist Nathaniel Kleitman who was the only person in the world at the time who had
spent his entire career studying sleep
o Kleitman had given his grad student Eugene Aserinsky the task of finding out whether
the slow, rolling eye movements that characterize the onset of sleep continue
throughout the night
o Found eye movements occur but they were rapid, not slow. Using
electroencephalography (EEG), these researchers including another of Kleitman’s
students William Dement were able to correlate the rapid eye movements with changes
in sleepers’ brain-wave patterns
Rapid Eye Movement (REM) sleep: sleep periods characterized by eye movement, loss of muscle
tone, and dreaming
Periods of REM sleep alternate with periods of fewer eye movements, non-REM (NREM) sleep,
in cycle that recurs every 90 minutes or so
REM periods last from a few minutes to as long as an hour, average about 20 minutes
Non-REM periods divided into distinct stages, each associated with particular brain-wave
pattern
When you first climb into bed, close your eyes, and relax, your brain emits bursts of alpha waves
Alpha waves have regular, slow rhythm and high amplitude (height). Gradually, waves slow
down even further, and drift into the Land of Nod, passing through four stages, each deeper
than the previous
o Stage 1. Your brain waves become small and irregular, and you feel yourself drifting on
the edge of consciousness, in a state of light sleep. If awakened, you may recall fantasies
or a few visual images
o Stage 2. Your brain emits occasional short bursts of rapid, high-peaking waves called
sleep spindles. Minor noises probably won't disturb you
o Stage 3. In addition to the waves that are characteristic of stage 2, your brain
occasionally emits delta waves, very slow waves with very high peaks. Your breathing
and pulse have slowed down, your muscles are relaxed, and you are hard to rouse o Stage 4. Delta waves have now largely taken over, and you are in deep sleep. It will
probably take vigorous shaking or a loud noise to awaken you. Oddly, though, if you
walk in your sleep, this is when you are likely to do so. No one yet knows what causes
sleepwalking, which occurs more often in children than adults, but it seems to involve
unusual patterns of delta-wave brain activity
Sequence takes 30-45 minutes then you move back up the ladder from 4-1. At this point, bout
70-90 minutes after onset of sleep, something peculiar happens
Stage 1 doesn’t turn into drowsy wakefulness, as one might suspect. Instead, your brain begins
to emit long bursts of very rapid, somewhat irregular waves. Heart rate increases, blood
pressure rises, and breathing speeds up and becomes more irregular. Small twitches in face and
fingers may occur; in men, the penis becomes somewhat erect as vascular tissue relaxes and
blood fills genital area faster than it exits; in women, clitoris enlarges and vaginal lubrication
increases. At same time, most skeletal muscles go limp, preventing aroused brain from
producing physical movement. Have entered realm of REM.
Brain extremely active while body is entirely inactive so REM sleep has been called “paradoxical
sleep”, vivid dreams occur here
o Dream reports occurred 82% of the time when sleepers were awakened during REM
sleep but they also occurred 51% of the time when people were awakened during non-
REM sleep
o Non-REM dreams tend to be shorter, less vivid, and more realistic than REM dreams,
except in the hour or so before a person wakes up in morning
Occasionally as sleeper wakes up, curious phenomenon occurs. Person emerges from REM sleep
before muscle paralysis characteristic of stage has entirely disappeared and becomes awake of
inability to move
o 30% of pop has experienced and about 5% had “waking” dream in state
o Eyes are open but “see” dreamlike hallucinations, mostly shadowy figures- may “see”
ghost or alien sitting on bed or hovering in hallway, scary image they would regard as
perfectly normal if part of midnight nightmare. Instead, some interpret experience
literally and believe they’ve been visited by aliens or being haunted
REM and non-REM sleep alternate throughout night, cycles far from regular
Reasons for REM sleep controversial
In some rare cases, brain-damaged patients lost capacity to dream yet continue to show normal
sleep stages including REM
All mammals experience REM sleep except for bottlenose dolphins and porpoises
“No one, but no one, has been able to come up with a convincing explanation for REM sleep” –
G.William Domhoff
Why We Sleep
Appears to provide time-out period so body can eliminate waste products from muscles, repair
cells, conserve or replenish energy stores, strengthen immune system, or recover abilities lost
during day
Bodies operate abnormally if don’t get enough sleep
o Levels of hormones necessary for normal muscle development and proper immune
system functioning decline
Sleep deprivation that lasts for four days or longer quite uncomfortable and soon becomes
unbearable o In animals, forced sleeplessness leads to infections and eventually death- same true for
people
o 51 year old man abruptly began to lose sleep- developed lung infection and died after
sinking deeper and deeper into exhausted stupor. Autopsy showed that he had lost
almost all of the large neurons in two areas of the thalamus that have been linked to
sleep and hormonal circadian rhythms
The Mental Consequences of Sleeplessness
Sleep necessary for normal mental functioning
Chronic sleep deprivation increases levels of the stress hormone cortisol which may damage or
impair brain cells that are necessary for learning and memory. New brain cells may either fail to
develop or may mature abnormally also
After loss of even single night’s sleep, mental flexibility, attention, and creativity all suffer
After several days of staying awake, people may even begin to have hallucinations and delusions
3.3 million Canadians (1/7 of people over 15) are plagued by chronic insomnia (difficulty falling
or staying asleep)
Insomnia can result from worry and anxiety, psychological problems, physical problems
(arthritis), and irregular or overly demanding work and study schedules
Canadian study of insomnia (Laval University’s Charles Morin), followed 400 insomniacs
undergoing treatment for condition- 54% improved with treatment but 27% relapsed afterward-
treatment only short-term solution
Sleep apnea: a disorder in which breathing briefly stops during sleep, causing the person to
choke and gasp and momentarily awaken
o Most seen in older males and overweight people
o Several causes from blockage of air passages to failure of brain to control respiration
correctly
o Can cause high blood pressure and irregular heartbeat; may gradually erode a person’s
health and is associated with shortened life expectancy over time
Narcolepsy: a sleep disorder involving sudden and unpredictable daytime attacks or sleepiness
or lapses into REM sleep
o Lasts from 5-30 minutes
o ~2700 Canadians suffer from condition without knowing
o Seems to be caused by degeneration of certain neurons in hypothalamus, possibly
owing to an autoimmune malfunction or genetic abnormalities
REM Behaviour Disorder: a disorder in which the muscle paralysis that normally occurs during
REM sleep is absent or incomplete, and the sleeper is able to act out his or her dream
o Usually male
o If dreaming about football, may try to tackle piece of furniture; if dreaming about kitten,
may try to pet
o Unaware of what he is doing
Two-thirds of all North Americans get fewer than recommended seven or eight hours of sleep
and students only get six on average
Some people do fine of relatively few hours of sleep but most adults need six for optimal
performance and many adolescents need ten
When people don’t get enough sleep, more likely to get into traffic or work accidents
In US, National Transportation Safety Board estimates that drowsiness is involved in 100 000
vehicle accidents a year, causing 1500 road deaths and 71 000 injuries Sleep deprivation also leads to accidents in workplace, concern especially for first-year doctors
doing medical residency
Many countries limit work hours for airline pilots, truck drivers, and nuclear-plant operators, but
medical residents still often work 24-30 hour shifts
Lack of sleep linked to lower grades
Sleep researcher James Maas noted that many high school and college students drag
themselves through day “like walking zombies… moody, lethargic, and unprepared or unable to
learn”
The Mental Benefits of Sleep
Study- students who slept for eight hours after learning lists of nonsense syllables retained them
better than students who went about their usual business
Scientists believe sleep plays more active role by contributing to consolidation: a process by
which they synaptic changes associated with recently stored memories become durable and
stable, causing memory to become more reliable
One theory is that during sleep the neural changes involved in recent memory are reactivated,
making those changes in memory more permanent
Improvements in memory have been associated most closely with REM sleep and slow-wave
sleep (stages 3 & 4) and with memory for specific motor and perceptual skills
Sleep also seems to strengthen other kinds of memories, including recollection of events,
locations, and facts
Emotional memories, especially, are improved with sleep: when people look at emotionally
arousing scenes in morning or evening and are then tested for their memory of materials after
12 hours of daytime wakefulness or nighttime sleep, those tested after sleeping recall the
emotional scenes more reliably that neutral ones
o Also do better on negative emotional scenes than other participants do
Sleep also enhances problem solving- relies on information stored in memory
We sleep to remember but we also sleep to forget so that brain will have space and energy for
new learning
Even quick nap helps mental functioning and increases ability to put together separately learned
facts in new ways
During sleep, periods of (REM) alternate with non-REM sleep in approximately a 90-minute
rhythm. Non-REM sleep is divided into four stages on the basis of characteristic brain-wave
patterns. During REM sleep, the brain is active, and there are other signs or arousal, yet most of
the skeletal muscles are limp; vivid dreams are reported most often during REM sleep. Some
people have had “waking dreams” when they emerge from REM sleep before the paralysis of
that stage has subsided and, occasionally, people have interpreted the resulting hallucinations
as real. The purposes of REM are still a matter of controversy
Sleep is necessary not only for bodily restoration but also for normal mental functioning. Many
people get less than the optimal amount of sleep. Some suffer from insomnia, sleep apnea,
narcolepsy, or REM behaviour disorder. Researchers are concerned about the growing number
of sleep-deprived people in modern societies
Sleep may be necessary for the consolidation of memories. Improvements in memory due to
sleep have been associated most closely with REM sleep and slow-wave sleep and with memory
for specific skills. Sleep also seems to improve insight and problem solving Exploring the Dream World
Every culture has theories about dreams
o In some, dreams are believed to occur when spirit leaves body to wander world or speak
to gods, in others, dreams thought to reveal future
Everybody dreams unless suffered some brain injury
In dreaming, focus of attention is inward but external event such as wailing siren, can influence
dream’s content occasionally
While dream is in progress, may be vivid or vague, terrifying or peaceful; may also seem to make
perfect sense- until awake and recall it as illogical, bizarre, and disjointed
Some say they occasionally have lucid dreams: dreams in which the dreamer is aware of
dreaming; few even claim to be able to control action in these dreams
Issue that has bothered sleep researchers for years is whether eye movements of REM sleep
correspond to events and actions in a dream.
o Are eyes tracking these images?
o Some believe that in adult dreamers, eye movements resemble those of waking life,
when eyes and head move in synchrony as person moves about and shifts gaze
o Others think eye movements are no more related to dream content than are inner-ear
muscle contractions which also occur during REM sleep
Dreams as Unconscious Wishes
One of first psychological theorists to take dreams seriously was Sigmund Freud- founder of
psychoanalysis
After analyzing many of patients’ dreams and some of his own, Freud concluded that our
nighttime fantasies provide insight into desires, movies, and conflicts of which we are unaware-
a “royal road to the unconscious”
In dreams, said Freud, we are able to express our unconscious wishes and desires, which are
often sexual or violent in nature
According to Freud, every dream is meaningful no matter how absurd images may seem
But if dream’s message arouses anxiety, rational part of mind must disguise and distort it
otherwise, dream would intrude into consciousness and waken dreamer
o Therefore, one person may be represented by another (ex. Father by a brother), or even
several different characters
o Similarly, thoughts and objects are translated into symbolic images. Penis may be
disguised as a snake, umbrella, or dagger; vagina as a tunnel or a cave; and human body
as house
Because reality is distorted, dream resembles psychosis, a severe mental disturbance; each
night, we must become temporarily delusional so that our anxiety will be kept at bay and sleep
won't be disturbed
To understand a dream, said Freud, we must distinguish its manifest content, the aspects of it
that we consciously experience dur
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