Bio Psych Exam 3

Sleepiness is NOT

a voluntary or optional act

endogenous circadian rhythms

internal mechanisms that operate on an approximately 24 hour cycle

Animals generate endogenous ____________

24 hour cycles of wakefulness and sleep

cycles similar to endogenous circadian rhythms

regulate the frequency of eating and drinking, body temperature, secretion of hormones, urination, sensitivity to drugs, mood, etc

Chronotypes

Cycles can differ between people and lead to different patterns of wakefulness and alertness

Typical Adolescent Chronotype

prefer to stay up late & get up late

Typical Older Adults Chronotype

prefer to go to bed early & get up early

free-running

when no external cues reset the human circadian rhythm

resetting circadian rhythms is ________

sometimes necessary

Zeitgeber

German for “time giver”; refers to any stimulus that entrains (updates & calibrates) the circadian rhythm

Examples of Zeitgeber

sunlight, tides, exercise, meals, arousal of any kind, meals, temperature of environment, etc

Phase delay

pushing our circadian rhythm back by falling asleep later than usual

Phase advance

pushing our circadian rhythm up by falling asleep sooner than usual

suprachiasmatic nucleus (SCN) is part of ____

hypothalamus

suprachiasmatic nucleus (SCN)

the main control center of the circadian rhythms of sleep and temperature

SCN generates _____

circadian rhythms in a genetically controlled manner: cells extracted from the SCN & maintained in a tissue culture continue to produce action potentials in rhythmic patterns

retinohypothalamic path

a small branch of the optic nerve

How does light reset the SCN

a small branch of the optic nerve known as the retinohypothalamic path

ganglion cells

specialized neurons located in the inner retina that act as the final output pathway, transmitting visual information from the eye to the brain

melanopsin

a blue-light-sensitive photopigment found in a subset of ganglion cells

Pineal gland

an endocrine gland located posterior to the thalamus which secretes melatonin

melatonin

a hormone that increases sleepiness

when does melatonin secretion begin

2-3 hours before bedtime

what does melatonin taken in the afternoon cause?

can cause phase advance

what does melatonin taken in the morning cause?

can cause phase delay

Two types of genes generate the circadian rhythm

Period and Timeless

Period

produces protein PER

Timeless

Produces protein TIM

what do PER and TIM do

increase the activity of some neurons in the SCN that regulate sleep and waking

What line is process-c on a graph of awakeness

the bottom dotted line

process-c

circadian (Wake drive)

What line is process-s on a graph of awakeness

top solid line w/ points

process-s

sleep drive

Hypnogram

shows typical “sleep architecture” (stage-to-stage progression through stages of sleep for an 8-hour evening; there is much variability from person to person)

Beta waves

present when one is awake and focused

Alpha waves

present when one enters state of relaxation

Stage 1 sleep is when

sleep has just begun

characteristics of stage 1 sleep

—> The EEG is dominated by jagged, irregular, low-voltage waves

—> Brain activity begins to decline; Stage 1 sometimes accompanied by dream-like hypnogogic sensations

hypnogogic sensations

vivid, often startling sensory experiences—such as feeling of falling, floating, or hearing sounds

Sleep spindles

12- to 14-Hz waves during a ½ second bursts

K-complex

a sharp high-amplitude negative wave followed by a smaller, slower positive wave

Stage 2 sleep is characterized by:

sleep spindles & k-complex

Stage 2 sleep is associated with:

Memory organization, hormone regulation, synaptic plasticity, physiological rest (relaxation)

slow wave sleep (SWS)

the third stage of non-REM sleep characterized by high-amplitude, low-frequency delta waves (0.5–2 Hz) in the EEG

Stage 3-4 sleep

slow wave sleep

Stage 3-4 sleep characterized by:

—> EEG shows slow, large-amplitude delta waves

—> Slowing of heart rate, breathing, and brain activity

—> Highly synchronized neuronal activity

Stage 3-4 sleep associated with:

Tissue repair, replenishing of immune system, growth processes, memory consolidation, flushing out metabolic byproducts (cleaning house)

Rapid eye movement sleep (REM)

periods characterized by rapid eye movements during sleep

REM sleep characterized by:

—> EEG waves are irregular, low-voltage, and fast

—>Postural muscles of the body are more relaxed than other stages

Rapid eye movement sleep (REM) is associated with:

Learning & memory, enhanced creativity, improved mood, brain development; neurotransmitter synthesis & replacement

Sleep spindle “transfer” of new memories ______ (Stage 2)

from temporary “flash drive” (hippocampus-based storage) to cortical-dependent long-term storage; consolidation of procedural motor memories

Replay and consolidation (stages 3 & 4)

of long-term, explicit memories (selective synaptic strengthening and weakening of memories)

Memory consolidation & “integration” (REM)

(restructuring, transformation, schematization) of new long-term explicit memories with older memories and general knowledge

Stage 3 sleep predominates

early in the night

REM sleep predominates

later in the night

SWS __________

decreases as the night goes on

REM ________

increases as the night goes on

PGO waves

Waves of neural activity are detected first in the pons, then in the lateral geniculate nucleus of the thalamus, and then the occipital cortex

PGO waves happen in what sleep stage

REM

REM deprivation results in _____

high density of PGO waves during uninterrupted sleep

Dreams vary by culture (Trobriand Islanders)

more uncles than fathers (uncles are disciplinarians)

Dreams vary by culture (Africa)

attacks by cows

Dreams vary by culture (Mexicans)

more images of death

Dreams vary by culture (Americans)

more public nud

Freud believed dreams served the two functions:

—> To guard sleep

—> To serve as sources of wish fulfillment

dream content varies by:

age, gender, and culture

Manifest content

the actual, surface-level imagery, events, and dialogue consciously recalled from a dream, film, or text, often serving as a disguise for underlying, hidden meaning

Latent content

the hidden, unconscious wishes, desires, and meanings expressed symbolically within dreams

the two biological theories of dreaming

—> Activation-synthesis

—> Neurocognitive model

why do we dream?

—> information processing hypothesis

—> activation-synthesis hypothesis

—> neurocognitive hypothesis

—> evolution hypothesis

Information-processing hypothesis

To integrate new information with old information.

Activation-synthesis hypothesis

Dreams begin with spontaneous activity in the pons, which activates parts of the cortex; the cortex synthesizes a “story” from the pattern of activation

Neurocognitive hypothesis

Dreams are just “thinking” under “unusual conditions”

—> Places less emphasis on the pons, PGO waves, or even REM sleep

—> Stimulation is combined with recent memories and information from the senses.

Evolutionary (and cognitive development) hypothesis

Dreams simulate reality, better preparing us for the waking world

pontomesencephalon

a part of the midbrain that contributes to cortical arousal

pontomesencephalon & axons

Axons extend to the hypothalamus, thalamus, & basal forebrain, which release acetylcholine & glutamate, and produce excitatory effects on widespread areas of the cortex

what does stimulation of the pontomesencephalon do?

awakens sleeping individuals and increases alertness in those already awake

ocus coeruleus

a small structure in the pons whose axons release norepinephrine to arouse various areas of the cortex and increase wakefulness

norepinephrine

a crucial neurotransmitter and hormone that increases heart rate, blood pressure, and alertness as part of the body's fight-or-flight response

hypothalamus contains _____

neurons that release histamine to produce widespread excitatory effects throughout the brain

histamine

acts as a key wake-promoting neurotransmitter in the brain, keeping you alert and awake

Antihistamne

produces sleepiness

Orexin

a peptide neurotransmitter released in a pathway from the lateral nucleus of the hypothalamus highly responsible for the ability to stay awake

Cells of the basal forebrain release the inhibitory neurotransmitter ___

GABA

GABA is important for _____

—> sleep

—> Decreasing temperature and metabolic rate, and stimulation of neurons

acetylcholine

is excitatory & increases arousal

Other axons from the basal forebrain release ________

release acetylcholine

Serotonin

its complicated

—> some 5-HT receptors promote sleep and facilitate entry into SWS

—> some 5-HT promote wakefulness & disrupt time in REM

Insomnia

a sleep disorder associated with inadequate sleep

Sleep apnea

a sleep disorder characterized by inability to breathe while sleeping for a prolonged period of time

Narcolepsy

a sleep disorder characterized by frequent periods of sleepiness, involving

—> Occasional cataplexy

—> Sleep paralysis

—> Hypnagogic hallucination

Occasional cataplexy

muscle weakness triggered by strong emotion

Sleep paralysis

inability to move while falling asleep or waking up

Hypnagogic hallucination

dreamlike experiences (usually at the onset of sleep) that are difficult to distinguish from reality

REM behavior disorder

associated with vigorous movement during REM sleep

Night terrors

experiences of intense anxiety from which a person awakens screaming in terror

Somnambulism “sleep walking”

runs in families, mostly occurs in young children, and occurs mostly in stage 3/4 (slow-wave) sleep

BMI Formula

(pounds x 0.45) / (( inches / 39.4))²) OR

(weight in kilogram) / (squared height in meters)

Obesity and Mortality

relative risk of death among healthy nonsmokers rises w/ extremely low or high BMI

Hunger

a combination of learned and unlearned factors that contribute to hunger & eating behavior