THE NATURE OF CONSCIOUSNESS: (chapter 5)
somniloque - sleep talking
narcolepsy - falling asleep uncontrollably during daily routines.
consciousness - the awareness of internal and external stimuli.
your consciousness is continuously changing - called the stream of
Mind wandering - peoples experience when they think of task unrelated
estimated 15-50% of time.
-studies show might occur less if the task is one that requires a lot of cognitive
-controlled (judgments or thoughts) and automatic processes (unconsciousness
or unintentional) experiment
i.e.) people rating faces unaware of associated smell
Malcom Gladwell's book "blink" - refers to how quickly and effortlessly our
judgments and choices are made.
consciousness does not arise from any area of the brain but rather from activity
in distributed networks of neural pathways.
electroencephalograph (EEG) - device that monitors the electrical activity of the
brain over time by means of recording electrodes attached to the surface of the
it summarizes the rhythm of cortical activity in the brain in terms of line tracings
called brain waves.
the brain waves vary in amplitude and frequency(cps)
human brain wave activity is usually divided into four principal bands based on
the frequency of the brain waves
1. beta (13-24 cps) - normal waking thought, alert problem solving
2. alpha (8-12 cps) - deep relaxation, blank mind, meditation.
3. theta (4-7 cps) - light sleep
4. delta (<4 cps)- deep sleep.
BIOLOGICAL RHYTHMS AND SLEEP:
biological rhythms - periodic fluctuations in physiological functioning's.
means humans have internal biological clocks that somehow monitor the
passage of time.
circadian rhythms - 24 hour biological cycles found in humans and many other
in humans - responsible for the regulation of sleep, blood pressure, urine
production and hormonal secretion. There are multiple biological clocks:
-when exposed to light retina sends direct inputs to a structure in the
hypothalamus called the superchiasmatic nucleus which sends a signal to the
pineal gland which may secrete appropriate hormones. (i.e. melatonin - sleep
-day light savings time: april (an hour forward) more accidents, no affect in the
jet lag: inferior state associated with measurable deficits in cognitive
performance, increase health problems.
flying westbound: have to stay up later
flying eastbound: time is later so bed time is earlier, people find this much
-melatonin decreases the effects.
lack of sleep: decrease immunity
carefully timed light exposure: can realign the circadian rhythms.
THE SLEEP AND WAKING CYCLE:
-electromyograph (EMG): Records muscular activity and tension
-electrooulograph (EOG) : records eye movement.
Awake: Low voltage high frequency beta waves.
drowsy: alpha waves prominent.
Stage 1: (1-7 minutes)
-transitional waves - theta waves prominent.
-breathing and heart rate slow
-lower frequency EEG (neurons doing things in sync for lower frequency)
hypnic jerks: brief muscular contractions before falling asleep
-bodily rates decline continuously.
sleep spindles occur (weird blimps)
stage 2 (10-25 minutes)
-mixed EEG activity
- spindles: brief bursts of higher frequency
-brain waves grow in amplitude and slower frequency toward "slow-wave sleep"
slow wave sleep: stages 3 & 4 during which high amplitude low frequency delta
waves become more prominent in EEG recordings. REM Sleep: (usually occurs after 90 minutes)
- rapid eye movement - closed eyes lateral movements.
-william dement: sleep researcher coined REM sleep.
-difficult to wake from, muscle tone is extremely relaxed
EEG dominated by high frequency beta waves that resemble hose observed
when people are alert and awake.
Caryl smith - psych prof at trent U. found correlations with sleep stages and
EX: stage 2 may be important for procedural motor type tasks. while REM sleep
may be important for complex logic type tasks.
The cycle changes gradually, first REM is relatively short and gets longer around
40-60 minutes in length.
Slow wave sleep occurs in early sleep cycle and REM piles up in the second half.
adults spend 15-20 percent in slow wave another 20-25 percent in REM.
The remainder of first year REM Portion of infants sleep declines 30%, continues
to decrease until it levels off at about 20% REM sleep remains fairly stable after
adult hood, slow wave sleep declines percentage spent in stage 1 increases
slightly. (these trends are stronger in men than women)
-may be contributing to increased frequency of night time awakening in elderly.
-recent study shows that extended sleep opportunities in elderly but need less
sleep than younger adults.
Co-sleeping: Parents and children sleeping together is discouraged in western
culture but encouraged in japanese culture (interdependence and group
"siesta cultures" - tropical regions: one two hour midday nap when shops close
IMPORTANT STRUCTURE: reticular formation: at the core of the brainstem
Ascending reticular activating system: afferent fibres running through the reticular
formation that influence physiological arousal.
-when ascending fibres that diffuse to other areas (afferent) are severed, the
result is continuous sleep.
-damage: causes coma, sleep-like EEG waves
-pons, midbrain, hypothalamus: critical to REM sleep.
-Medulla, thalamus and basal forebrain have also been noted in the control of
sleep regulation: Horomones and neurotransmitters as well. RESEARCH ON SLEEP DEPRIVATION:
-partial sleep deprivation/sleep restrictions: occur when people make do with
less sleep than normal over a period of time.
Experiments: Students giving up 24 hours performed poorly in cognitive tasks but
rated their effort, concentration and performance higher than normal routine
-sleep deprived people are not good at predicting when and if they will sleep.
Matthew walker - 35 hours awake group exposing series of photos (neutral to
negative). assessed the activity of the brain through fMRI. Amygdalas more
active in the sleep deprived.
Sleep deprivation: Type of partial sleep deprivation investigated by
-REM deprivation causes increase of REM in sleep cycle.
-slow wave sleep deprivation, more awakenings, people experience a rebound
memory consolidation: General effect of learning from daytime experience.
Neurogenesis: Formation of new neurons
Insomina: Chronic problems in getting adequate sleep.
- excessive anxiety, tension, side effects of emotional problems. ( depression),
stress, health problems.
-some people are predisposed because they have a higher level of physiological
arrousal than most.
-hyper arousal model: people exhibit hormonal patterns that fuel arousal,
elevated heart rate, high metabolic activation, increased body temperature and
EEG patterns associated with arousal.
benzodiazepine sedatives (made for anxiety)
non benzodiazepine sedatives (designed for sleep problems)
Narcolepsy: Sudden irresistible onset of sleep during normal waking periods.
-wakefulness to REM sleep (sleep lasts 10-20 minutes)
-some are genetically predisposed
-stimulant drugs to treat condition also can cause serious side effects
Sleep apnea: Frequent reflexive gasping for air that awake a person and
disputes sleep. accompanied with loud snoring, correlated with heart problems.
-increases vulnerability to hyper tension, coronary disease and stroke.
-2% women, 4% men between ages 30-60 treatment: Lifestyle modifications (weight loss, reduced alcohol intake, drug
therapy, special masks and oral devices )
Nightmares: Anxiety-arousing dreams that lead to awakening usually from REM
-stage 1. (about 7 hours of sleep)
-awaken and have difficulty falling back asleep.
-children should attend counselling.
night terror "sleep terrors": abrupt awakening from NREM sleep, accompanied
by intense autonomic arousal and feeling of panic.
-stage 4 (within 2-3 hours of sleep)
Somnanabulism "sleep talking": 15 seconds - 30 minutes)
-occurs when a person rises and starts to wander while remaining asleep.
-stage 3 (within first hour)
-not related to emotional or psychological problems
REM sleep behaviour disorder (RBD):
Marked by potentially troublesome dream enactment during REM periods(can be
-typically in men in 50-60 yrs old
-some sort of detonation in brainstem structures responsible for immobility during
-may coexist with other sleep orders.
dream: REM sleep that processes a visual story-like experience.
-non REM stages of sleep, dreams appear less vivid, visual and story like.
-mental processes of sleep more similar to waking thought processes than
-tolerant of logical discrepancies and implausible scenarios.