Psych: Consciousness

Circadian rhythm

  • Any rhythmic change that continues at close to a 24-hour cycle in the absence of 24-hour cues

    -body temp

    -cortisol secretion

    -sleep and wakefulness

  • In the absence of tie cues, the cycle period will become somewhat longer than 24hours

The Body’’s Clock

  • suprachiasmatic nucleus (SCN)— cluster of neurons in the hypothalamus that governs the timing of circadian rhythms

  • melatonin—hormone of the pineal gland that produces sleepiness

Electroencephalogram (EEG)

  • electrodes placed on the scalp provide a gross record of the electrical activity of the brain

  • EEG recording are a rough index of psychological states

EEG waves of wakefulness

  • Awake, but-non attentive: large, regular alpha waves

  • Awake and attentive: low amplitude, fast, irregular beta waves.

Stages of sleep

Sleep stage 1: brief transition stage when first falling asleep

Stages 2 through 4 (slow-wave sleep): successively deeper stages of sleep

Characterized by an increased percentage of slow, irregular, high-amplitude delta waves

Upon reaching stage 4 and after about 80 to 100 minutes of total sleep time, sleep lightens, returns through stages 3 and 2

REM sleep emerges, characterized by EEG patterns that resemble beta waves of alert wakefulness

-muscles most relaxed

-rapid eye movements occur

-dreams occur

Four or five sleep cycles occur in a typical nights sleep; less time is spent in slow-wave, more is spent in REM

Functions of Sleep

  • Restoration theory— body wears out during the day and sleep is required to put it back in shape

  • Adaptive theory— sleep emerged evolution to preserve energy and protect during the time of day when there is little value and considerable danger

Sleep Deprivation

  • Affects performance of physical skills or intellectual judgement

Individual sleep differences

  • Some individuals need more and some less than typical 8 hours of sleep

    • Nonsomiacs— sleep less than most, but do not feel tired during the day

    • Insomniacs— have a normal desire for sleep, but are unable to and feel tired during the day

SLEEP DISORDERS

Insomnia- inability to fall asleep or stay asleep

REM sleep disorder- acting our dreams

Night terrors- sudden arousal from sleep and intense fear accompanied by physiological reactions that occur during slow-wave sleep

Narcolepsy- overpowering urge to fall asleep that may over while talking or standing up

Sleep apnea- failure to breathe when asleep

Sleepwalking- walking or performing actions in stage 3-4 sleep

Sleep Bruxism- loudly grinding teeth

Sleep related Eating Disorder- compulsively eating while sleep walking

Sexsomnia - compulsive sexual behavior during sleep

True Dream- vivid, detailed dreams consisting of sensory and motor sensations experienced during REM

Sleep thought- lacks vivid sensory and motor sensations, is more similar to daytime thnking and occurs during slow-wave sleep

Dreams and REM sleep

  • Dreams can occur in REM and NREM but more detailed, frequent and longer in REM

  • Dreams have five basic characteristics:

    -intense emotional content

    -illogical organization

    -bizarre sensations

    -weird details uncritically accepted

    -difficult to remember

REM Brain Activity

  • Distinctly different from NREM

  • Visual cortex and frontal lobe shut down

  • amygdala and hippocampus highly active

  • increased activity in association cortex

  • transition from NREM to REM abrupt

  • REM helps consolidate memories

WHAT ARE DREAM FOR?

  1. Psychoanalytica Interpretation

  • Manifest content—elements of the dream that are consciously experienced and remembered

  • Latent conten—the unconscious wishes that are concealed in the manifest content

  • Dreams as “wish fulfillments”

  1. Activation Synthesis Model

  • Brain activity during sleep produces dream images which are combined by the brain into a dream story

  • Meaning is to be found by analyzing the way the dreamer makes sense of the progression of chaotic dream images

  1. Neurocognition Theory

  • Continuity between waking and dreaming cognition

  • Dreams reflect our interests, personalities and individual worries

  • Dreams occur because we are cut off from external world so we generate our own sensory data