Consciousness + Biology of sleep

Consciousness

The awareness of objects + events in external world + of our sensations + mental experiences at any given moment
-psychological state
-self awareness of external + internal stimuli
-an experience, personal , selective, continuous and changing

Normal Waking Consciousness vs Altered State of Consciousness

Awareness of internal states + external surroundings when awake, unaffected by sleep, drugs, or other states

Any other state outside of normal waking consciousness
-lack of awareness (self + emotional), perceptions of time, surroundings
-sleep + daydream occur naturally
-others are induced, e.g meditation, hypnosis, alcohol ingestion, meds + drugs

Sleep - altered State of Consciousness

Reversible behavioural state of perceptual disengagement + unresponsiveness to environment
-lack of conscious awareness, sensory stimuli + unresponsive to stimuli

Suprachiasmatic nucleus

Controls circadian rhythms. (sleep wake cycles that occur approximately every 24 hours)

-detects amount light being sent from eyes (signal) → brain 4 processing (pineal gland) → influence amount of melatonin release →bloodstream

Melatonin

Secreted by pineal gland, keeps track of body’s natural cycles + register external factors e.g light, incudes drowsiness + sleep

Reticular Activating System (RAS)
-network of neurons, extends out from RF → diff parts of brain + spinal cord
-major parts = reticular formation + thalamus

RAS = Influences when asleep + awake
involved in attention, initiates attention response (selective attention)

RF = reduces stimuli sent to cerebral cortex
regulates transition btwn sleep + wakefulness
stimulated = alertness, damaged = coma

Thalamus + damage

Minimizes sensory pathways during sleep
-filters + transfers all sensory info (X smell) to relevant parts of brain 4 processing
-transfers neural information (alertness + attention) RF → cerebral cortex

loss of any sense, cerebral cortex no receive sensory info
lower arousal (coma, lethargy), attention difficulties, no filter, don’t know what ignore, what attend