elements of consciousness

conciousness

knowing or being aware of ongoing experiences (internal and external reality)

self-awareness

understanding of the self as distinct from other stimuli

which brain structures are associated with consciousness?

cerebral cortex, thalamus, reticular formation, and the pathways connecting them

mind wandering

when your thought is unfocused

default mode network (DMN)

• maintains high level of unconscious

• background activity as it helps brain prepare for conscious thought

• activity is correlated with thinking about self, others, and person’s past + future

connectivity of the DMN

• functional = cognitive function

• abnormal = autism, alzheimer’s

content of awareness

ongoing catalog of internal and external stimuli that are the focus of current situation

biological clocks

internal mechanism that provides approx schedule for various physical processes

zeitgebers

• internal biological clocks interact with these external, stimuli

  • ex. —> exposure to light (sun) helps reset internal biological clocks to correct time

circadian rhythm

natural, approx 24-hour internal clock that governs sleep-wake cycles, hormone release, digestion, and temp

major depressive disorder with seasonal patterns

• aka seasonal affective disorder (SAD)

• depression occurs regularly at the same time each year

• usually winter months (less light)

what accounts for differences in sleep patterns?

• can be a genetic basis of circadian rhythms

• may be age-related (adolescence + young adulthood —> night people)

beta waves

• waveform of 15 - 30 cycles per second on electroencephalogram

• indicates alert waking

alpha waves

• waveform of 9 - 12 cycles per second on electroencephalogram

• indicates relaxed waking

gamma waves

• waveform of more than 30 cycles per second on EEG

• indicates attention to sensory input

daydreaming

• mind wandering

• spontaneous, subjective experiences in a no-task, no-stimulus, no-response situation

• activity in the DMN

what do we think about during activation of the DMN?

past experiences and plan our future (during daydreaming)

two types of sleep

• rapid eye movement sleep (REM)

• non-rapid eye movement sleep (N-REM)

rapid eye movement (REM) sleep

• waveforms resemble waking

• rapid motion of the eyes

• muscular paralysis

• sympathetic nervous system activation

• rapid/irregular heart rate, blood pressure, breathing

non-rapid eye movement (N-REM) sleep

• theta and delta wave activity (drowsiness)

• deep physical relaxation

sleep spindles and K complexes

indicate brain’s attempts to tune out environmental stimuli during N-REM sleep

stages of N-REM sleep

• stage 1 and 2 = theta waves (drowsy)

• stage 2 —> sleep spindles and K complexes

• stage 3 and 4 = delta waves, deepest stages of sleep

theta waves

• waveform of 4 - 7 cycles per second

• lighter stages of N-REM sleep

stage 1 of N-REM sleep

• theta waves

• people not aware that they are sleeping

• person usually deny they were asleep when waken up

stage 2 of N-REM sleep

• person is def asleep

• reduction in heart rate and muscle tension

• K complexes and sleep spindles

  • spindles = consolidation of memory (inc frequency after pre-sleep learning)

sleep spindles

• reflect activity association with consolidation of memories

  • freq inc after pre-sleep learning

  • dec freq = alzheimer’s and > cognitive func

stage 3 and 4 of N-REM sleep

• delta wave

• stage 4 = most delta activity

• deeply asleep

• waking from stage 4 is difficult

• repairing body

• release of human growth hormone

delta wave

• waveform of 1 - 4 cycles per second

• indicates deep N-REM sleep

paradoxical sleep

• first episode of REM sleep

• occurs between 90 - 120 mins after onset of sleep

• brain resembling waking while appearing to be in deep sleep

sleepwalking

occurs during stage 3 or 4 of N-REM sleep

pattern of REM and N-REM sleep

• first half of night sleep = longer N-REM and shorter REM sleep

  • stage 3 and 4 are dominant in first 4 hours

• second half of night sleep = REM is dominant, N-REM is shorter

  • stage 3 and 4 less freq during last 4 hours

• last half hour = REM sleep, wake up with awareness of dreaming

effects of sleep deprivation

• slows healing

• reduce immune system activity

• prod of fewer new neurons

REM rebound

body’s recovery of REM sleep after a period of deprivation

REM sleep as a function of relative maturity at birth

more maturity indicates less REM sleep

dreaming

mental state during sleep that features visual imagery

activation-synthesis theory

content of dreams represents the mind’s efforts to make sense out of real physical sensations

• vestibular system is active = info abt position of head = dreams of flying/falling

• dreams of being unable to move = muscle paralysis during REM sleep

how are daydreaming and dreaming on a continuum?

dreaming behavior correlates with activity that overlaps with DMN

dreaming process

• as you shift into dreaming, brainstem changes awareness of external stimuli

• frontal lobe activity drops (associated with logic, self-awareness)

• once dreaming starts, brain pulls from memories, general knowledge, and personal experiences to create a storyline

lucid dreaming

• conscious awareness of dreaming with the ability to control the dream

• frontal areas of brain “wake up” during a dream

  • inc activity in dorsolateral prefrontal cortex (control)

nightmares

• occur in REM sleep

• upsetting content

• can be controlled in lucid dreaming

sleep terrors

• occur in N-REM sleep

• sleeper wakes in great distress without experiencing the imagery of a nightmare

insomnia

person has difficulty maintaining or initiating sleep

two forms of insomnia

• onset insomnia

• maintenance insomnia

onset insomnia

• person lies in bed for long time but can’t sleep

• causes are stress and anxiety

maintenance insomnia

• sleep in freq interrupted or early waking occurs

• causes are stress, substance use, psych disorders

bluelight glasses

prevent the negative consequences of light before sleep, which interfere with melatonin

narcolepsy

• rapid eye movement into waking (while awake)

• absence of orexins (regulate sleep, arousal, appetite)

cataplexy

muscle paralysis associated with REM sleep occurs during wakefulness

how to resolve sleep paralysis

touch the person

sleep apnea

• person stops breathing while asleep

• occurs in people who are obese and snore

• brainstorm neurons that maintain breathing also may malfunction

sudden infant death syndrome (SIDS)

healthy infant dies while asleep

ways to combat SIDS

• put infants to sleep on their backs

• use firm sleep surface

• room-sharing, no bed-sharing

• no soft bedding and overheating

• no exposure to smoke, alcohol, illicit drugs

• breastfeeding

• use of pacifiers

• skin-to-skin care

restless leg syndrome (RLS)

involuntary movement of limbs, usually leg (tingly feeling, moves at reg intervals)

prosopagnosia

affects person’s ability to recognize faces

capgras syndrome

patients are convinced that imposters have taken the place of familiar people

coma

• state of deep unconsciousness resulting from brain damage or illness

• disruptions in reticular formation or both cerebral hemispheres

alpha coma

• after resuscitation from cardiac arrest

• pattern of alpha rhythms, esp in frontal lobes

vegetative state (VS)

• waking without consciousness, following brain injury

• look normal (eyes open, demonstrate sleep + waking cycles, scream, smile, cry)

brain death

irreversible loss of all functions of the brain including brainstem

near-death experience

• state of consciousness reported by people close to death

• out-of-body experience

  • also occur when using ketamine

  • brain might release chemicals similar to ketamine to minimize cell loss

• light-at-end-of-tunnel perceptions

• state of calmness

seizures

• uncontrolled electrical disturbances in the brain

• produce changes in consciousness

epilepsy

reoccurring seizures

causes of seizures

• brain injury or infection

• disturbances in neurotransmitter GABA

  • inhibit GABA = seizures

  • enhance GABA = control of seizures

two kinds of seizures

partial or generalized

partial seizures

• originate in part of brain called focal area

• comes with premonition that seizure will occur

• distortion of consciousness —> deja vu, jamais vu

generalized seizures

• abnormal activation of circuits btwn cortex and thalamus

• no premonition

• consciousness is completely lost

• tonic-clonic and absence seizures

deja vu

• “already seen”

• feeling that you are reliving the past

jamais vu

• “never seen”

• familiar circumstances are suddenly forgotten or strange

two categories of generalized seizures

tonic-clonic and absence seizures

tonic-clonic seizures

• loss of consciousness

• cessation of breathing

• intense muscular contraction

• may result in breaking bones + other injuries

• followed by 5-minute comas

absence seizure

• loses consciousness and awareness of surroundings

• motor movements are limited

• only blinking, head turns, eye movements

psychoactive drugs

substances that can alter consciousness

tolerance

need to administer more of a drug to achieve the desired effects

withdrawal

• physical responses to removal of a drug

• slows down NS

• rebound effect = more brain activity activity —> seizures

addiction

compulsive physical/psychological dependence on a substance or activity in spite of negative consequences

causes of poor decision-making from addiction (disruptions in)

• impulsive system = dopamine pathways connecting midbrain + basal ganglia

• reflective system = frontal lobes (weighs pros and cons of decision)

• craving system = insula (craving for drug of choice)

  • damage to insula —> no more urge to use addictive drugs

cannabis

• natural form of marijuana

• experience of excitation, vivid imagery, mild euphoria

• others response with depression, social withdrawal

• distorts perception of time + prod hallucinations

• hallucinogen

hallucinogen

drug that stimulates hallucinations

tetrahydrocannabinol (THC)

• cannabinoid (psychoactive compound of cannabis)

• interacts with receptors of endogenous cannabinoids

lysergic acid diethylamide (LSD)

• interacts with serotonin receptors

• vivid, colorful hallucinations

• dec connectivity in DMN

• inc activity in visual cortex

• experience of flashbacks (even after discontinuation)

caffeine

• interferes with inhibition produced by adenosine in the brain

• inc excitation and alertness

• stimulant

• reduced rates of growth if entered into breast milk

• withdrawal —> headaches + fatigue

stimulant

drug that inc activity of the NS

nicotine

• mimics action of acetylcholine (ACh)

• inc heart rate, blood pressure

• reduced fatigue, improved cognitive performance, muscle relaxation

cocaine and amphetamines

• alertness, elevate mood, confidence, sense of well-being

• higher doses = symptoms like those of schizophrenia

methaphetamine

• common abused form of amphetamines

• leads to symptoms of psychosis

• stimulates grinding of teeth —> dental decay (“meth mouth”)

how do amphetamines (methamphetamine) act at the synapse?

• mimics dopamine, moves out of synaptic gap into neurons by dopamine transporters

• enters synaptic vesicles, pushing out dopamine molecules into fluid of axon terminal

• transporters push large amounts of dopamine out of the cell

• dopamine molecules become trapped in synaptic gap, stimulating receptors

how does cocaine act at the synapse?

• blocks the dopamine transporters

• keeps all released dopamine in the synaptic gap —> receptors

methylphenidate (ritalin)

• drug for ADHD

• boost activity of dopamine + norepinephrine

  • increase user’s ability to stay alert

adderall

• combo of amphetamine salts

• boost dopamine + norepinephrine

• inc user’s ability to stay alert

MDMA (ecstasy)

• inc heart rate, blood pressure, body temp

• inc activity of serotonin and oxytocin —> inc sociability

• excess serotonin (OD of antidepressants) —> serotonin syndrome

serotonin syndrome

• excess serotonin activity from MDMA use

• dehydration, exhaustion, hyperthermia, convulsions, death

effects of alcohol

• dilates blood vessels (warm, flushed feeling)

• reduces anxiety

• high doses —> risky behaviors, poor motor coordination, aggression

• very high —> coma, death

• boosts GABA (inhibitor), depresses brain activity

opioids

• interact with endorphins

• releases large amounts of dopamine

  • feelings of well-being, reduction of pain

hypnosis

• state of consciousness involving focused attention and reduced peripheral awareness

  • enhanced capacity for response to suggestion

meditation

• voluntary alteration of consciousness

• positive emotion, absence of thought

• increased alpha waves

• decreased activation of DMN = feelings of bliss