AP Psych: States of Consciousness

Circadian Rhythm

the natural, internal process that regulates the sleep-wake cycle and other bodily functions, typically repeating every 24 hours.

suprachiasmatic nucleus (SCN)

small region of hypothalamus, responsible for regulating circadian rhythm

non-rapid-eye-movement sleep (NREM)

stage of sleep without rapid eye movement, divided into three substages

Rapid-eye-movement (REM) sleep (aka paradoxical sleep)

stage of sleep characterized by a lack of postural tension, rapid eye movements, and vivid dreaming.It is associated with heightened brain activity and plays a crucial role in memory consolidation.

Beta waves

brain waves associated with alertness and active thinking, measuring 13-30 Hz.

Alpha waves

brain waves associated with relaxed wakefulness, measuring 8-12 Hz.

NREM 1

small amplitude EEG waves of irregular frequency (theta waves). Often found in hippocampus.  Hallucinations often occur in this stage (falling/floating).  Hypnagogic jerks occur here (involuntary muscle twitch, often causing person to jump and momentarily awaken).NREM Stage 1 is the initial stage of non-REM sleep, characterized by light sleep where the transition from wakefulness occurs. It involves the presence of theta waves and can include hypnagogic hallucinations and jerks.

NREM 2

theta waves continue, with frequency bursts called sleep spindles and K-complexes that help protect sleep and support memory consolidation. This stage is deeper than NREM 1 and accounts for approximately 50% of total sleep.

NREM 3

defined by the presence of high amplitude, low frequency waves (delta waves). Often found in thalamus.  Deep sleep; often stage where bedwetting occurs

Sleep Theory

A framework that explains the functions and mechanisms of sleep, including why we sleep and how it affects our mental and physical health.

Ghrelin

A hormone produced in the stomach that stimulates appetite, increasing food intake and promoting fat storage.

Cortisol

A steroid hormone produced by the adrenal glands, often released in response to stress, playing a role in various bodily functions including metabolism and immune response.

Leptin

A hormone produced by adipose (fat) tissue that helps to regulate energy balance by inhibiting hunger, thereby promoting satiety.

Insomnia

A sleep disorder characterized by difficulty falling or staying asleep, leading to daytime fatigue and impaired functioning. Worsened by sleeping pills/alcohol (also reduces REM sleep). causes can be genetic, drug use/withdrawal, hormonal shifts, heart disease, deviated septumor anxiety disorders.

Narcolepsy

sleep disorder characterized by uncontrollable sleep attacks, sometimes lapsing directly into REM sleep, usually lasts for several minutes

-Typically due to absence of hypothalamic neural cluster that secretes hypocretin (neurotransmitter linked to alertness)

Sleep Apnea

sleep disorder characterized by temporary cessations of breathing during sleep, resulting in momentary awakenings.  Decreased blood oxygen awakens them to snort in air.

-Associated with obesity

Night Terrors

sleep disorder characterized by high arousal and appearance of being terrified.  Occur during NREM-3.  

-Mostly affects children.  Includes sitting up, walking around, incoherent speech/screaming.  Seldom wake up if not awaken by another.

Sleepwalking/talking (Somnambulism)

 typically occurs during NREM-3, usually in preteens.  Actions/words are simple and repeat over multiple episodes.  Typically harmless, very rarely remembered.

Sleep Paralysis

Temporary inability to move when waking up or falling asleep.  Occurs chronically in approx. 5% of people.  Often hear humming/static/ hissing/zapping sounds.  May also hallucinate (typically “monster-like” creatures or shadowy figure approaching).

-Believed that this is due to overlapping sleep stages?

-Subjects tend to experience shorter sleep cycles

-Also strong correlation between occurrences and sleep deprivation

Dreams

 a sequence of images, emotions, and thoughts passing through a sleeping person’s mind.

-Notable for hallucinatory imagery, discontinuities, incongruity, delusional acceptance, and difficulty remembering

-Common themes: failure, being attacked/pursued/ rejected, experiencing misfortune

-Often incorporate traces of previous day’s non- sexual experiences

-According to Freud, we dream to satisfy our wishes, as well as discharge unacceptable feelings

Manifest content:

the remembered storyline of a dream.  The censored, symbolic version of a dream’s latent content (underlying meaning of a dream).