states of consciousness

Biological rhythms

Internal rhythms of biological activity.

Circadian rhythm

A biological rhythm that takes place over a period of about 24 hours.

Suprachiasmatic nucleus (SCN)

Area in the hypothalamus where the brain's clock is located.

Pineal gland

Gland that releases melatonin when darkness is perceived.

Chronotype

Differences in circadian rhythms, such as being a morning person vs. a night person.

Sleep deprivation

Associated with obesity, increased blood pressure, increased levels of stress hormones, and reduced immune functioning.

Sleep rebound

The phenomenon where a sleep-deprived individual will fall asleep more quickly during subsequent opportunities for sleep.

Evolutionary psychology

Discipline that studies how universal patterns of behavior and cognitive processes have evolved over time due to natural selection.

Beta waves

High frequency, low amplitude brain waves that occur during wakefulness.

NREM sleep

Sleep characterized by low frequency and high amplitude brain waves, occurring as you start to fall asleep.

Alpha waves

Brain waves that occur during stage 1 sleep, characterized by high amplitude and low frequency.

Theta waves

Brain waves present during stage 1 sleep, characterized by even lower frequency and higher amplitude than alpha waves.

Sleep spindle

A rapid burst of higher frequency brain waves that may be important for learning and memory.

K complex

A very high amplitude pattern of brain activity that may occur in response to environmental stimuli.

Stage 2 sleep

Sleep stage dominated by theta waves, with brief interruptions from sleep spindles and k complexes.

Delta waves

Waves with the lowest frequency and highest amplitude, occurring during stage 3 sleep.

Manifest content vs. latent content

Manifest content is the storyline of dreams, while latent content is the hidden meaning, a theory developed by Freud.

Rosalind Cartwright

The only psychologist to have empirical evidence for her theory of dreams; noted that dream content reflects what is on the mind of the dreamer.

Parasomnias

A group of sleep disorders involving unwanted, disruptive motor activity and/or experiences during sleep.

Somnambulism

Sleepwalking disorder.

REM sleep behavior disorder (RBD)

Occurs when muscle paralysis associated with the REM sleep phase does not happen, leading to disturbing dreams and physical activity.

Central vs. obstructive sleep apnea

Disruption in brain signals regulating breathing causes interrupted breathing (central) vs. blocked airways (obstructive).

SIDS

Sudden Infant Death Syndrome; occurs when an infant stops breathing during sleep and dies.