Biological Rhythms and Sleep Ch 10

The Mind’s Machine. (5th ed.)

Circadian rhythms

About a day (24 hr period)

Biological rhythms that last about a day and occur in numerous physiological measures.

Ultradian rhythms

Beyond (more than once/day)

REM/NonREM cycle

Biological rhythms that repeat more than once per day, such as feeding or hormone release.

Infradian rhythms

Biological rhythms that take more than a day, repeating less than once per day, e.g., menstrual cycle.

Suprachiasmatic nucleus (SCN)

a small region of the brain located in the hypothalamus that regulates circadian rhythms by receiving light information from the retina.

Phase shift

The shift of activity produced by a synchronizing stimulus that alters circadian rhythms.

Zeitgeber

“Time giver” - A stimulus that entrain circadian rhythms

Any external cue an animal uses to synchronize its biological rhythms with the environment.

Free-running

A condition in which an animal maintains its own personal cycle without external cues.

Atonia

The complete absence of muscle tone that occurs during REM sleep.

Sleep-waking cycle

The daily cycle of sleep and wakefulness regulated by biological rhythms.

Slow-wave sleep (SWS)

Stage 3 of non-REM sleep characterized by large-amplitude, very slow delta waves.

Melatonin

a hormone produced by the pineal gland that helps regulate sleep-wake cycles and is influenced by light exposure.

Electroencephalography (EEG)

A method to record electrical activity in the brain to differentiate sleep stages.

Rapid-eye-movement (REM) sleep

The stage of sleep characterized by rapid eye movements and vivid dreaming.

Sleep spindles

Rapid bursts of brain activity occur during NREM sleep, primarily in Stage 2. They are thought to play a role in memory processing and brain synchronization.

Cataplexy

A sudden loss of muscle tone often triggered by strong emotions, associated with narcolepsy.

Night terrors

A sleep disorder characterized by episodes of intense fear and panic, occurring during deep sleep, often accompanied by thrashing or screaming while still asleep. The sleeper does not recall a vivid dream but may remember crushing feelings.

Sleep maintenance insomnia

Difficulty in remaining asleep, often characterized by frequent nighttime awakenings.

Fatal familial insomnia

A rare genetic disorder leading to a complete loss of sleep, eventually resulting in death.

Orexin (hypocretin)

A neuropeptide involved in regulating wakefulness and playing a role in narcolepsy.

Somnambulism

Also known as sleepwalking, a behavior where individuals perform activities while asleep.

These episodes occur during stage 3 SWS.

Sleep recovery

The process of making up for lost sleep, including increased amounts of deep sleep stages.

Jet lag

The mismatch between internal biological time and external time after traveling across time zones.

REM behavior disorder (RBD)

A condition where individuals act out their dreams due to lack of muscle paralysis during REM.

K complexes

High-amplitude waveforms that occur in NREM sleep, particularly during Stage 2. They are believed to be involved in the brain's response to stimuli and contribute to sleep stability.

Bruxism

Medication-related teeth grinding that occurs during sleep.

Insomnia

Difficulty falling asleep or staying asleep that can affect daytime functioning.

Hypersomnolence

Excessive daytime sleepiness not due to sleep deprivation or other sleep disorders.

Circadian misalignment

The lack of synchronization between the internal biological clock and external environmental cues.

Night owls

Individuals who have a preference for staying up late and waking up later.

Early birds

Individuals who prefer to go to bed early and wake up early.

Vigilance

The state of being alert and attentive, which can be impacted by sleep deprivation.

Chronotype

Individual differences in the timing of sleep and activity, often categorized as larks or owls.

Sleep hygiene

Practices that promote consistent quality sleep, including maintaining a sleep schedule.

Physiological measures

Various indicators, such as hormone levels and body temperature, that change throughout the day.

Glymphatic system

A waste clearance system in the brain that operates during sleep, removing toxins.

Cognitive deficits

Impairments in cognitive function, often linked with lack of adequate sleep.

Paradoxical sleep

A stage of sleep characterized by rapid eye movements (REM), heightened brain activity, and vivid dreams, often referred to as REM sleep.

Biological Rhythms

Regular fluctuations in any living process.

Patterns of physiological or behavioral changes that follow a regular cycle, influenced by external cues like light and temperature.

Entrainment

the process of synchronizing a biological rhythm with an external stimulus such as light or temperature cues.

retinohypothalamic pathway

a neural pathway that transmits light information from the retina to the suprachiasmatic nucleus, helping to synchronize circadian rhythms.

melanopsin

a photopigment found in certain retinal ganglion cells that plays a crucial role in regulating circadian rhythms by responding to ambient light.

non-REM sleep

A stage of sleep that is divided into several sub-stages, characterized by slower brain waves, reduced eye movement, and absence of vivid dreaming. It is essential for physical restoration and recovery.

desynchronized EEG

Also referred to as beta activity- a pattern of electrical activity seen during alert wakefulness or REM sleep, marked by low-amplitude, mixed-frequency waves. It indicates high levels of brain activity.

alpha rhythm

a pattern of brain wave activity typically observed when a person is awake but relaxed, characterized by rhythmic oscillations in the frequency range of 8 to 12 Hz, indicating a state of calm alertness.

Vertex Spike

A sharp wave pattern often seen in EEG recordings during sleep, particularly in stage NREM 2. It is associated with sleep spindles and may indicate a brief disruption in cortical activity.

Stage 1 Sleep

The transition phase between wakefulness and sleep, characterized by light sleep where muscle activity slows and awareness of the external environment diminishes. It typically lasts a few minutes and may include moments of muscle jerks.

Stage 2 sleep

a deeper sleep stage following Stage 1, marked by sleep spindles and K-complexes in EEG patterns. It comprises about 45-55% of total sleep time and plays a crucial role in memory consolidation.

Stage 3 sleep

a deep sleep stage characterized by slow delta waves. It is vital for physical restoration and growth, comprising about 15-25% of total sleep time.

Growth hormone is secreted primarily during this stage

In humans, the most dramatic decline - Reaching 60 years old spend only about half as much time in this stage as they did at age 20. By age 90, it has disappeared.

loss of growth hormone due to disrupted sleep in the elderly leads to cognitive deficits

Loss of SWS probably also impairs memory processes in older people and people with dementia

Delta Waves

Slow brain waves associated with deep sleep, particularly Stage 3. They play a crucial role in restorative processes and are indicative of sleep depth.

Nightmares

Unpleasant dreams that cause distress, often leading to awakening. Unlike night terrors, they occur during REM sleep and are more vivid.

Sleep deprivation

A condition resulting from inadequate sleep, leading to cognitive impairments, mood changes, and various health issues.

Fatal familial insomnia

A rare genetic disorder that leads to progressively worsening insomnia, resulting in severe cognitive decline, loss of motor control, and ultimately death.

ecological niche

The role and position a species has in its environment, including its habitat, resource use, and interactions with other organisms.

basal forebrain

A group of structures in the brain critical for regulating sleep, wakefulness, and arousal.

tuberomammillary nucleus

A cluster of neurons located in the posterior hypothalamus that plays a key role in promoting wakefulness and regulating sleep-wake cycles.

general anesthetics

drugs such as barbiturates and anesthetic gases that render people unconscious during surgery.

A forebrain system

that includes structures like the basal forebrain and tuberomammillary nucleus, involved in regulating arousal and sleep. Generates SWS

A brainstem system

activates the sleeping forebrain into wakefulness

A pontine system

triggers REM sleep

A hypothalamic system

coordinates the other three brain regions to determine which state we’re in

Reticular formation

is a network within the brainstem that regulates arousal and consciousness, influencing sleep-wake cycles.

Locus Coeruleus

is a nucleus in the pons that produces norepinephrine, playing a crucial role in regulating attention, response to stress, and sleep-wake cycles.

Narcolepsy

A sleep disorder characterized by frequent intense episodes of sleep and sudden sleep attacks. It lasts 5-30 mins and can occur any time during usual waking hours.

Caused by loss of orexin signaling.

Sleep paralysis

e temporary inability to move or talk either just before dropping off to sleep or, more often, just after waking.It is often accompanied by hallucinations and a feeling of pressure on the chest.

sleep enuresis

(bed-wetting)—are associated with SWS. A condition often seen in children, involving involuntary urination during sleep.

sleep-onset insomnia

a difficulty in falling asleep.

Sleep state misperception

A condition where individuals perceive they have not slept or have slept less than they actually have, leading to distress or impairment.

sleep apnea

arises either from the progressive relaxation of muscles of the chest, diaphragm, and throat cavity or from changes in the pacemaker respiratory neurons of the brainstem. It is characterized by repeated interruptions in breathing during sleep, leading to poor sleep quality and daytime fatigue.

sudden infant death syndrome (SIDS)

A sudden and unexplained death of an infant, typically during sleep, often occurring in infants under one year of age. Also known as crib death that may be associated with sleep position, environmental factors, or underlying health issues.

What is narcolepsy, and what brain system seems to be responsible for this disorder?

Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness, sudden sleep attacks, and cataplexy. It is thought to involve dysfunction in the brain's hypocretin system, which regulates wakefulness and REM sleep.

During what stage of sleep does sleepwalking tend to happen? During what time of night?

Sleepwalking typically occurs during non-REM sleep, specifically in stages 3 or 4. This usually happens in the first third of the night.

What are the different types of insomnia, and why are sleeping pills an imperfect long-term solution?

Insomnia includes types such as acute, chronic, and transient. Sleeping pills can address symptoms but do not resolve underlying issues like stress or anxiety that contribute to insomnia.

Describe REM behavior disorder.

REM behavior disorder is a sleep disorder characterized by the absence of normal muscle paralysis during REM sleep, causing individuals to act out their dreams. This disorder can lead to injury to themselves or their partners.