Chapter 6 flash cards (AI)

Chapter 6 Consciousness and Sleep

Biological Rhythms, are periodic, more or less regular fluctuation in a biological system, often having psychological implications.

These rhythms are based on both external and endogenous cues

Circadian rhythms are biological rhythms with a ~24 hour periodicity

Circadian rhythms are controlled by a biological clock, or overall coordinator, located in a tiny cluster of cells in the hypothalamus called the suprachiasmatic

Neural pathways from special receptors in the back of the eye transmit information to the Suprachiasmatic nucleus (SCN), allowing it to respond to changes in light and dark.

SCN innervates pineal gland to stimulate release of melatonin

Melatonin accumulates with darkness and onset of sleep

The usual circadian rhythms are thrown out of phase with one another.

When our normal routine changes, we may experience internal desynchronization

This can occur when people take airplane flights across several time zones. Sleep and wake patterns usually adjust quickly, but temperature and hormone cycles can take several days to return to normal.

Also can happen when adjusting to new shift at work

Jet lag affects energy level, mental skills, motor coordination.

Seasons effect mood: some people experience depression during particular seasons, typically winter, in a pattern that has been labeled seasonal affective disorder (S A D)

Sleep stages

REM sleep: active brain, but inactive muscles. REM periods last from a few minutes to as long as an hour, averaging about 20 minutes in length. Whenever they begin, the pattern of electrical activity from the sleeper’s brain changes to resemble that of alert wakefulness.

Stage 1. Your brain waves are small and irregular, and you feel yourself drifting on the edge of consciousness, in a state of light sleep. If awakened, you may recall fantasies or a few visual images. ALPHA to THETA

Stage 2. Sleeping stage, when your brain emits occasional short bursts of rapid, high-peaking waves called sleep spindles. Minor noises probably won’t disturb you.

Stage 3/4. Your brain emits delta waves, very slow waves with very high peaks, and you are in deep sleep. Your breathing and pulse have slowed down, your muscles are relaxed, and it will probably take vigorous shaking or a loud noise to awaken you. Oddly, though, if you walk in your sleep, this is when you are likely to do so. No one yet knows what causes sleepwalking, which occurs more often in children than adults, but it seems to involve unusual patterns of delta-wave activity

During rapid eye movement (R E M) sleep, the brain is active, and there are other signs of arousal.

Most of the skeletal muscles are limp.

Vivid dreams are reported most often during R E M sleep.

R E M and non-R E M sleep continue to alternate throughout the night

Why do we sleep? (Hypothesis)

Restore and Repair Hypothesis: The idea that the body needs to restore energy levels and repair any wear and tear experienced during the day’s activities.

Preserve and Protect hypothesis: Suggests that two more adaptive functions of sleep are preserving energy and protecting the organism from harm.

Consequences of sleep loss:

Chronic sleep deprivation increases levels of the stress hormone cortisol, which may damage or impair brain cells that are necessary for learning and memory. fteAlso, new brain cells may either fail to develop or may mature abnormally

After several all-nighters you may start to hallucinate

Fun facts

There is no ‘magic number’ for sleep

Amount of sleep needed varies between individuals according to age and genetics

Sleep is developmentally important

Insomnia types

Onset insomnia: difficulty falling asleep

Maintenance insomnia: difficulty returning to sleep

Terminal insomnia: waking too early

Can be further classified as:

Primary insomnia: due to internal source (e.g., worrying)

Secondary insomnias: result of other disorders

Movement disturbances:

Restless legs syndrome: persistent discomfort in the legs and the urge to continuously shift them into different position

REM sleep behavior disorder is when someone acts out dreams - due to failure to inhibit motor signals

Somnambulism (sleepwalking): a disorder that involves wandering and performing other activities while asleep

Sleep disorders and causes of daytime sleepiness:

Sleep apnea: a disorder in which breathing periodically stops for a few moments, causing the person to choke and gasp (airway becomes obstructed)

Usually due to obesity or damage to medulla

Narcolepsy: a disorder where an individual is subject to irresistible and unpredictable daytime sleepiness and sleep attacks lasting from 5 to 30 minutes

They fall Immediately into REM sleep

REM behavior disorder: when the muscle paralysis associated with REM sleep does not occur, the sleeper becomes physically active, often acting out a dream without any awareness of what they are doing

Sleep benefits / theories:

Most believe that sleep is a crucial time for consolidation, in which synaptic changes associated with recently stored memories become durable and stable.

One theory is that while we are sleeping, the neurons that were activated during the original experience are reactivated, promoting the transfer of memories from temporary storage in the hippocampus to long-term storage in the cortex.

Sleep seems to strengthen many kinds of memories, including the recollection of events, facts, and emotional experiences, especially negative ones

REM facilitates learning, especially for complex tasks

Late REM phases, are especially important for ‘locking in’ learning

Dreams as Efforts to Deal with Problems

Dreams reflect conscious preoccupations of waking life, e.g., concerns over relationships, work, sex, or health.

Symbols and metaphors in a dream do not disguise its true meaning; they convey it.

Supported by findings that dreams are more likely to contain material related to a person’s current concerns than chance would predict.

Dreams reflect waking concerns and provide opportunity to resolve them.

This is a problem focused explanation because: (cons)

Some psychologists doubt that people can solve problems during sleep.

Dreams merely give expression to our problems.

The same insights obtained from dreaming could occur while awake.

Dreams as Thinking

The cognitive approach:

Emphasizes current concerns, makes no claims about problem-solving during sleep.

Dreams include thoughts and scenarios that may or may not relate to our daily problems.

Brain does same kind of work during dreams as when awake.

The difference is that during sleep:

We are cut off from sensory input from the world.

Our thoughts tend to be more diffuse and unfocused.

The only input to the brain is its own output.

The cognitive approach to dreams is promising, but some of its claims remain to be tested against neurological and cognitive evidence. At present, however, it is a leading contender because it incorporates many elements of other theories and fits what we currently know about waking cognition and cognitive development.

Dreams as Interpreted Brain Activity

The Activation synthesis theory is the belief that dreams occur when the cortex tries to make sense of, or interpret, spontaneous neural firing initiated in the pons.

Dreams result from the cortex’s synthesis of:

signals from pons

existing knowledge

Memories in this view, wishes do not cause dreams; brain mechanisms do.

Cons:

The activation–synthesis theory has been criticized, as it does not seem to explain:

coherent, story-like dreams

non-R E M dreams

The cognitive approach is now a leading contender.

Some of its specific claims remain to be tested.

Perhaps it will turn out that different kinds of dreams have different purposes and origins.

Hypnosis

Hypnosis is a procedure in which the practitioner suggests changes in a subject’s: sensations, thoughts, feelings, behavior

Theories:

Dissociation Theory is a leading approach to understanding hypnosis is that it involves dissociation, a split in consciousness.

In one version of this approach, the split is between:

a part of consciousness that is hypnotized

a hidden observer that watches but does not participate

In another version, the split is between:

an executive-control system in the brain

other brain systems responsible for thinking and acting

In hypnosis, the executive system turns off and hands its function over to the hypnotist.

That leaves the hypnotist able to suggest how we should interpret the world and act in it.

The sociocongitve explanation regards hypnosis as a product of normal social and cognitive processes.

There is a combination of: the hypnotized person’s expectations and beliefs the desire to comply with the hypnotist’s suggestions

In this view, hypnosis is a form of role-playing.

The role is so engrossing that the person interprets it as real.

Biological theories

Alpha waves common when a person is in a relaxed hypnotic state; brain scans permit more detailed picture happenings in hypnotized person’s brain.

Hypnosis involves changes in the control of attention, the “central executive” network of the brain.

Hypnosis can reduce conflict between two mental tasks.

“Stroop effect” virtually disappeared for highly suggestible group.

Disorders of Consciousness

Brain death: condition in which the brain stem no longer functions

No potential for recovery

Coma: complete loss of consciousness

Body is still aside from minor twitches

No pupillary response

Persistent vegetative state (PVS): a state of minimal to no consciousness

Eyes open but do not track movement

Normal sleep cycles

Best hope for recovery before 6 months

The case of Terry Shiavo (family keeping their daughter alive on tubes for 6 years, husband wanted to give up after a year or so) this case changed whos allowed to make decisions and how long its ok to let them be

Consciousness in the unconscious

Some PVS patients show signs of consciousness

fMRI suggests comprehension of commands and mental imagery

Misdiagnosis of vegetative state?

Disorder continued:

Minimally conscious state: marked by the ability to show some behaviours that suggest partial consciousness, even if on an inconsistent basis

Behaviours beyond reflexes

Locked-in syndrome: patient is aware and awake but, because of an inability to move, appears unconscious

Cognitive and emotional processing intact

Drugs:

Drugs affect neurotransmitter activity through various agonistic and antagonistic effects

Nucleus accumbens: A prime area of activation when a person engages in rewarding behavior

Tolerance is when repeated use of a drug results in a need for a higher dose to get the intended effect

Physical dependence the need to take a drug to ward off unpleasant physical withdrawal

Psychological dependence is the need to take a drug to ward off negative emotions (No physical symptoms)

Experience with a drug changes response (ex marijuana)

Context-dependent overdoses

Anticipatory drug response (your brain and body know when you're getting ready to use, so it prepares for it) - this is only if you do it in the same place or with same ppl etc, ex basement vs park, if youve never done it in the park you may OD

Commonly Abused Drugs

Stimulants: drugs that speed up the nervous system, typically enhancing wakefulness and alertness ex cocaine, amphetamines, ecstasy

Euphoria, increased energy, lowered inhibitions, Increased dopamine, serotonin, norepinephrine

Tolerance develops quickly

High risk of dependence

Physical deterioration

Hygiene neglected

Drug cocktail often includes ingredients such as hydrochloric acid and farm fertilizer

Cognitive deterioration

Structural abnormalities in cells of the frontal lobes

Users develop difficulties ignoring irrelevant thoughts

Stroop test

Sedatives (downers) depress activity of the central nervous system ex Xanax, Valium

Drowsiness, relaxation, sleep

Increase GABA activity

Tolerance develops quickly

High risk of dependence

Barbiturates vs benzodiazepines

Hallousingens produce perceptual distortions ex: LSD, ketamine, DMT, psilocybin, salvia

Divinorum

Experiences range from euphoria to fear, panic, paranoia

Increased serotonin, blocks glutamate receptors

Tolerance develops slowly

Low risk of dependence

Opioties (narcotics) reduce pain and induce extremely intense feelings of euphoria ex morphine, heroin, fentanyl, oxycodone, oxycontin, codeine, opium

Intense euphoria, pain relief

Stimulate endorphin receptors

Tolerance develops very quickly

Very high risk of dependence

Alcohol: most commonly used drug

Euphoria, relaxation, lowered inhibitions

Increase GABA activity, then stimulates endorphin and dopamine receptors

Tolerance develops gradually

Moderate-high risk of dependence

Biphasic effect

Marijuana: made from the leaves and buds of the Cannabis plant

Euphoria, relaxation, distorted sensory experiences, paranoia

THC mimics brain chemicals (anandamide) involved in sleep and memory by binding to cannabinoid receptors

Tolerance develops slowly

Lower risk of dependence

Marjuana effects on the brain: Impairs memory, executive functioning, and motor coordination

Worse memory, attention, and decision making than controls

Altered brain activity compared to controls even when successfully completing tasks

Distribution of cannabinoid receptors in the brain correspond to cognitive deficits

Expectations can be even more powerful than the drug itself, as shown by the “think drink” effect

This does not mean that alcohol and other drugs are merely placebos.

Psychoactive drugs have physiological effects, many of them extremely potent.

These findings suggest that mere expectation of a drug’s effects can produce at least some of those effects.