CHP.2 SLEEP

consciousness

the state of being aware of and responsive to one’s surroundings, including one’s own thoughts, feelings, and sensations

hypnosis

an induced, altered state of consciousness that heightens a person’s openness to responding to suggestion without losing his or her sense of self control

circadian rhythm

• a 24-hour cycle biological clock

• body temp rises and sets with the sun, reaching its peak at noon

jet lag

a disruption of the circadian rhythm, typically a byproduct of time zone changes

shift work

working specific time shifts that misalign with the circadian rhythm

melatonin

• a “sleep” hormone secreted in the bloodstream

• production is signaled to start by darkness, and signaled to end with light

EEG machine

monitors brain activity and can be used to measure the stages of sleep

beta waves

when you’re awake, active, and alert

alpha waves

when you’re relaxed, drowsy, or meditating

theta waves

when you’re in light sleep, predominantly in NREM stage 1

delta waves

when you’re in deep sleep, predominantly in NREM stage 3

NREM stage 1 sleep

• lightest stage of sleep, often retaining awareness of surrounding stimuli

• only lasts one to five minutes

NREM stage 2 sleep

• the stage in which the most time sleeping is spent

• lasts around twenty minutes, whilst heart rate slows and breathing shallows

• time spent in this stage gets longer as the night progresses

NREM stage 3 sleep

• as the night goes on, time spent in this stage diminishes

• if awoken, an individual would be groggy and disoriented

• vital for restoring body’s growth hormones and for good overall health

hypnagogic sensations

• mild sensations, often of falling

• signature to NREM stage 1

REM sleep

• rapid eye moment, around every half minute your eyes dart around

• 20% of sleep time is spent here, with roughly 5 cycles per night, lasting 15-45 minutes out of every 90 minutes

• when the most dreams occur, leading to elevated heart rate and rapid breathing

paradoxical sleep

• motor cortex is active, but the brainstem blocks its messages to the rest of your body, preventing motion despite dreams

• brain is extremely active, yet the body is paralyzed

REM rebound

the tendency for REM sleep to increase following REM sleep deprivation

activation synthesis theory

• our cerebral cortex is attempting to interpret random electrical activity that we have while asleep

• the brain area processes visual images by result of stimulation, hence why dreams tend to make little sense

  • active; limbic system (emotional center) & amygdala (fear and aggro center)

  • idle; frontal lobe (logic, judgment, and reason center)

consolidation theory

• the brain uses REM sleep periods and dreams as a means to sift, sort, and fix the day’s experiences in our memory

• brain scans confirm a link between the amount of REM sleep acquired and memory

insomnia

• persistent problems in falling asleep and staying asleep

• most common sleep complaint among americans, found in 1/5 adults

• some causes include stress, worrying, changing circadian rhythms, medical problems, and substance abuse

narcolepsy

• marked by excessive sleepiness that may cause an individual to fall asleep at unpredictable or inappropriate times

• “sleep attacks” lasting one to five minutes, directly into REM sleep

• a result of a hypocretin deficiency (?)

REM sleep behaviour disorder

• normal REM paralysis by result of brain-stem blockage does not occur, causing twitching, talking, or in severe cases attacking to occur

sleep apnea

• a person stops breathing in their sleep for ten seconds or longer, causing them to wake up momentarily to gasp for air (snore)

• affects 1/20 people, especially prevalent in heavy males

• deprives NREM stage 3 sleep, and can be fatal

somnambulism

• sleep walking, occurring in NREM stage 3 sleep in the earlier sleep hours

• affects 1/15 people, can be genetically linked

• usually occurs when an individual is stressed or sleep deprived

psychoactive drugs

chemicals that affect the brain

tolerance

the diminishing effect with regular use of the same dose of a drug, requiring a user to take larger and larger doses in an attempt to chase the desired effect

addiction

compulsive substance use that continues despite harmful consequences

withdrawal

the discomfort and distress that follows discontinuing an addictive drug or behaviour

depressants

• drugs that calm neural activity and slow body functions

  • ex. alcohol, opioids

alcohol

• slows neural processing, self-awareness, and brain activity that controls judgment and movement

• disrupts the memory and increases harmful tendencies

opioids

• serves as an agonist for endorphins, while slowing neural activity and temporarily lessening pain and anxiety

  • ex. heroin

stimulants

• excites neural activity and speeds up bodily functions

  • ex. caffeine, cocaine

• pupils dilate, heart rate and breathing hasten, blood sugar levels rise, appetite reduces, energy and self-confidence increase

caffeine

• the world’s most widely consumed psychoactive substance

• mild dose can last three to four hours, impairing sleep, boosting blood pressure, and leading to heartburn or ulcers

• like most other drugs, can create tolerance and cause withdrawal

  • withdrawal symptoms include fatigue and headaches

cocaine

• a powerful, addictive stimulant that can be snorted, injected, or smoked

• enters the bloodstream quickly, producing a rush of euphoria that depletes the brain’s supply of the neurotransmitters dopamine, serotonin, and norepinephrine

• may lead to emotional disturbances, suspiciousness, convulsions, cardiac arrest, and respiratory failure

hallucinogens

• distorts perceptions and evokes sensory images in the absence of sensory input, which is why they are often also referred to as psychedelics

  • ex. marijuana

marajuana

• can be consumed (slow) or inhaled (quick)

• contains THC, which may induce psychiatric symptoms such as hallucinations, delusions, and anxiety. may also amplify sensitivity to external stimuli, and lingers in the body for more than a week

• impairs motor coordination, perceptual skills, reaction time, memory formation, and attention span

heroin

• a type of opioid that offers a blissful pleasure that replaces pain and anxiety

• causes the user’s pupils to contract, breathing to slow, and lethargy to kick in