Exam 5 Psychobiology

Sleep and Stress

Three Standard Psychophysiological Measures of Sleep

• Electroencephalogram (EEG)

• Electrooculogram (EOG)

• Electromyogram (EMG)

Three Stages of Sleep EEG

• Stage 1

• Low voltage, fast activity

• Stage 2

• K complexes and sleep spindles

• Stage 3

• Delta waves

• Emergent stage 1 EEG

• REM or paradoxical sleep

• 90-minute cycles

Alpha waves

waxing and waning burst of 8-12 burst Hz EEG waves

• began to punctuate the low voltage, high frequency waves of alert wakefulness

Delta waves

The largest and slowest EEG waves

• frequency of 1 -2 Hz

K complex

Is a single large negative wave followed by a single large positive wave

Two theories of sleep

Recuperation theories

• Restores homeostasis

• Restore energy

• Clear toxins from the brain

• Restore synaptic plasticity

Adaptive theories

• Conserve energy

• Protect organisms

REM Sleep

Sleep characterized by rapid eye movements and emergent stage 1 EEG

NREM 3 is also refered to as?

Slow wave sleep: stage 3 sleep were it is characterized by the largest and slowest EEG waves

Comparative Analysis of Sleep

• All mammals and most birds sleep

• Not uniquely human - not special, higher-order function

• Not needed in large amounts

• Correlated to vulnerability

Effects of Sleep Deprivation

The Stress Problem –

• Most people who are deprived of sleep is because of stress

• Difficult to separate the effects of sleep loss from the effects of stress

• Like which one causes which?

Recuperation theory predictions

Excessive wakefulness results in debilitating physiological deficits

• Deficits will worsen with more sleep deprivation

• After sleep deprivation ends, sleep will be regained

Lucid Dreaming

Is the ability to be aware that one is dreaming and in some cases be able to control the contents of ones dream

Sleep-deprived students

Those subjects that continued in the study continued to exhibit a wavelike increase and decrease in sleep around the same time every night

Randy Gardner

• 11 days awake

• Slept 14 hours the first

Total sleep deprivation several days

• No marked physiological disturbances

• Sleepiness

• Mood disturbances

• Problems maintaining vigilance

• Microsleeps

• Poor executive function

Microsleeps

A brief period of sleep typically last 2 to 3 seconds

Carousel Apparatus

Used to deprive rats of sleep

REM-Sleep Deprivation

As time goes by, must awaken more often

• REM rebound

Tricyclic antidepressants

block REM

Sleep Deprivation Increases the Efficiency of Sleep

Individuals deprived of sleep become more efficient sleepers

• Their sleep has a higher proportion of slow-wave sleep (NREM 3)

• Six pieces of evidence

Circadian rhythms

• Sleep–wake cycle

• Entrainment

• Zeitgebers

Zeitgebers

Emotional cues such as light dark cycle that entertain circadian rhythms

Free running rhythms

rhythms that do not depend on enviormental cues to keep them on a regular scedule

Free running period

The duration of one cycle of a free running rhythm

Internal desynchronization

More than one circadian mechanism

Circadian theory of sleep

Supported by negative correlation between periods of wakefulness and sleep

Jet lag and shift work

• Phase advanced or phase delayed zeitgebers

• Sleep disturbances, fatigue, and performance decrements

• Phase advance harder than phase delay

Circadian clock

An internal timing mechanisms that is capable of maintaining daily cycles of physiological functions

Suprachiasmatic nucleus

(SCN) Nuclei of the medial hypothalamus that control the circaridan cycles of the various body functions

Two Areas of the Hypothalamus Involved in Sleep

• Posterior portion of hypothalamus - wakefulness

• Anterior portion of hypothalamus - sleep

Melanopsin

A protein and photopigment found in a specialized type of retinal ganglion cells called intrinsically photosensitive retinal ganglion cells

Active theory of sleep

• Brain stem lesions (caudal end)

• Cerveau isolé and the reticular activating system

• Stimulation of reticular activating system

Moruzzi and Magoun

• Low levels of activity produce sleep

• High levels produce wakefulness

Regions of reticular formation and REM sleep

• Reduction of core-muscle tone

• EEG desynchronization

• Rapid eye movement

Hypnotic Drugs

Sleep promoting Drugs

Antihypnotic Drugs

Sleep reducing drugs

Benzodiazepines

• Increase drowsiness, reduce awakenings, increase sleep time

• Pitfalls include tolerance, addiction, distort normal sleep patterns, next day drowsiness,

reduced lifespan

midazopyridines

• Zolpidem GABAA agonist

• No safer or more effective than benzodiazepines

Antihypnotic Drugs

• Cocaine-derived stimulants, amphetamine-derived stimulants, and tricyclic antidepressants

Melatonin

• Synthesized in pineal gland

• Pineal gland releases in rhythms

• Promotes sleep

• Possible chronobiotic

Pineal Gland

The humans body sole source of melatonin

Common Beliefs About Dreaming

• Dreams run on real time

• Everyone dreams

• External stimuli incorperated into the dreams

The Dreaming Brain

• Brain lesions produce a cessation of dreaming

• Bilateral lesions of the tempero-parieto junction

• Bilateral lesions of the medial prefrontal cortex

• Areas of secondary visual cortex in the medial occipital lobe lead to a loss of

visual imagery in dreams

Phineas Gage (1848)

A reconstruction of the brain injury of Phineas Gage. The damage focused on the medial prefrontal lobes

• Tamping iron through medial prefrontal lobes

• Changed personality forever

Darwin’s theory of evolution (1872)

• First biopsychological bases of emotion

• Emotions evolved from telegraphed behavior

• Principle of antithesis

The principle of antithesis

The aggressive posture of dogs features ears forward, back up, hair up, and tail up; the submissive posture features ears back, back down, hair down, and tail down.

Emotion

A subjective mental state usually accompanied by distinctive behaviors and involuntary physiological changes.

Sympathetic nervous system

“fight or flight” system; activates the body for action

Parasympathetic nervous system

prepares the body to relax and recuperate

James-Lange theory

• Physiological basis of emotion

• Emotion-inducing stimuli trigger visceral changes

• Results in experience of emotion

Cannon-Bard theory

• Emotional stimuli evoke independent visceral and emotional responses

Modern view

• Interaction between perception of emotional stimulus, autonomic/somatic responses, and experience of emotion

Sham Rage

exaggerated poorly directed aggressive response

Limbic system

• Papez

• Controls expression of emotions

Klüver-Bucy syndrome

• Damage to amygdala

• Fearless, hypersexual, and

explores objects with mouth

Polygraphy

• Examine changes in emotions through ANS

• Control-question technique

• Guilty-knowledge technique

Control question technique

A lie detection interigation method that in which the polygrapher compares the physioloigcal responses to target questions

Guilty knowledge technique

Reads autonomic nervous system responses known only to a guilty person

Facial Feedback Hypothesis

The hypo that our facial expresions can influence the emotions we experience

Duchenne (genuine smile)

A smile that moves all the right muscles

Psychoneuroimmunology

The study of interactions among psychological factors, immune system and nervous system

Eustress

Good stress

Distress

Bad stress

Stress and the Hippocampus

• Hippocampus more susceptible to stress effects

• Shrinking of dendrites

• Reduced neurogenesis

How does stress influence immune function?

Changes in body and behavior

What are the three standard physiological measures of sleep?

EEG (brain activity), EOG (eye movement), and EMG (muscle tension)

What's the difference between REM and non-REM sleep?

REM involves rapid eye movement, vivid dreams, and muscle atonia

Non-REM includes deeper sleep stages and less brain activity

What do recuperation theories suggest about sleep?

Sleep restores energy, clears toxins, and restores synaptic plasticity lost during wakefulness.

What are the 4 conclusions from adaptation theories of sleep?

1. Sleep has a physiological function.

2. Sleep isn't just for higher-order human functions.

3. We don't need a lot of sleep to survive.

4. Sleep duration is related to how vulnerable a species is while sleeping.

What are three predictions of recuperation theory regarding sleep deprivation?

1. Long wakefulness leads to deficits.

2. Deficits worsen over time.

3. Lost sleep will be recovered.

What did the Randy Gardner case show about sleep deprivation?

Severe sleep loss causes deficits, but they aren't as permanent or extreme as once thought.

What is REM rebound?

Increased REM sleep after deprivation, suggesting its importance

What are zeitgebers?

Environmental cues, like light, that help regulate circadian rhythms.

What is a free-running rhythm?

A circadian cycle that runs without external cues often slightly longer than 24 hours.

What is internal desynchronization?

When different circadian rhythms (e.g., sleep and body temp) go out of sync

What's the difference between jet lag and shift work?

Jet lag = changed zeitgeber; shift work = same zeitgeber but altered behavior

Name two ways to reduce effects of jet lag/shift work.

Gradual schedule shifts and exposure to bright light at appropriate times.

Which part of the brain contains the circadian clock?

Suprachiasmatic nucleus (SCN) of the hypothalamus.

What do the anterior and posterior hypothalamus regulate?

Anterior = sleep; Posterior = wakefulness.

What is the reticular activating system?

A brainstem system that promotes wakefulness.

What are the three classes of hypnotic drugs?

Benzodiazepines, Imidazopyridines (like Ambien), and melatonin.

What are the three classes of antihypnotic drugs?

Stimulants, tricyclic antidepressants, and orexin agonists

What's the relationship between REM and dreaming?

Dreaming is most common during REM, but can also occur in non-REM sleep.

Name three brain regions involved in dreaming.

Temporo-parietal junction, medial prefrontal cortex, and medial occipital lobe.

What's the main idea of the James-Lange theory?

Emotion is the result of bodily changes (we feel afraid because we tremble).

What brain structure is affected in Kluver-Bucy syndrome?

Amygdala - causes lack of fear, oral behaviors, and hypersexuality.

What are Ekman's six primary facial expressions?

Happiness, sadness, anger, fear, disgust, and surprise.

What is the Duchenne smile?

A genuine smile involving both mouth and eye muscles.

What role does the amygdala play in fear?

It's essential for learning, expressing, and storing fear responses

What happens to fear conditioning if the hippocampus is lesioned?

Contextual fear (environment-related fear) is impaired.

What hormone is released from the adrenal cortex during stress?

Cortisol (a glucocorticoid).

What are cytokines?

Immune-system messengers involved in inflammation.

What is subordination stress?

Chronic stress caused by social hierarchy (like bullying)

How does chronic stress affect the hippocampus?

Reduces dendrite length and decreases neurogenesis.