Sleep and Biological Rhythms - Carlson Chapter 9

Comprehensive practice flashcards covering sleep stages, disorders, neurochemical pathways, and biological rhythms based on Carlson Chapter 9 and associated lectures.

What is the general relationship between neural activity and EEG wave amplitude and frequency?

High neural activity results in low-amplitude, high-frequency waves ($small, fast$), whereas low neural activity results in high-amplitude, low-frequency waves ($big, slow$).

Rank the four main EEG wave types in order from highest to lowest frequency.

$$beta > alpha > theta > delta$$

What are the characteristic EEG features of alert waking (Beta activity)?

Irregular, low-amplitude, desynchronized waves with a frequency between $13-30\,Hz$.

Which two specific EEG anomalies define Stage 2 sleep?

Sleep spindles (short $12-14\,Hz$ bursts) and K complexes (sudden sharp large waveforms) occurring on a background of theta activity.

How are Stage 3 and Stage 4 sleep defined based on delta activity?

Stage 3 contains $20-50\%$ delta activity, while Stage 4 contains more than $50\%$ delta activity.

Why is REM sleep often referred to as 'paradoxical sleep'?

Because the EEG appears desynchronized with mixed theta and beta activity similar to light wakefulness, even though the person is deeply asleep and paralyzed.

According to Roffwarg et al. (1962), what is the relationship between REM eye movements and dream content?

Eye movements often match where the dreamer reports looking, and brain regions relevant to dreamed events (like motor or speech regions) activate as if the events were actually happening.

How does sleep architecture (the stages of sleep) change across a typical 8-hour night?

Sleep occurs in repeated cycles of approximately $90$ minutes; slow-wave sleep (Stages 3-4) is concentrated in the first half of the night, while REM periods get progressively longer toward the second half.

What are the three common patterns of insomnia?

(1) Trouble falling asleep, (2) frequent waking through the night, and (3) waking very early (e.g., $2-4\,a.m.$) and being unable to return to sleep.

Distinguish between central sleep apnea and obstructive sleep apnea.

Central sleep apnea involves the brain's $CO_2$-sensing drive to breathe temporarily dulling; obstructive sleep apnea is caused by a physical airway obstruction, such as the collapse of the soft palate.

List the four classic symptoms of narcolepsy.

Sleep attacks, cataplexy (sudden paralysis while awake), sleep paralysis (failure to move just before or after sleep), and hypnagogic hallucinations (vivid dream-like experiences during paralysis).

What typically triggers a cataplectic attack in a narcolepsy patient?

Intense emotional arousal such as laughter, excitement, or anger.

How does REM sleep behavior disorder (RBD) differ from ordinary sleepwalking?

In RBD, the patient fails to become paralyzed during REM and physically acts out a dream world they are fully immersed in; sleepwalking occurs during slow-wave sleep and involves complex behavior without full conscious awareness.

What is Fatal Familial Insomnia (FFI)?

An extremely rare inherited prion disease causing progressive insomnia, cognitive decline, and autonomic dysfunction leading to death; it is characterized by damage to the thalamus.

What specific types of memory consolidation are facilitated by REM sleep versus slow-wave sleep?

REM sleep facilitates nondeclarative (procedural/perceptual) memory, while slow-wave sleep facilitates declarative memory.

What is the function of adenosine in the neurochemistry of sleep?

An inhibitory neuromodulator that accumulates during wakefulness due to astrocyte glycogen use, promoting sleepiness; it is cleared during slow-wave sleep.

Which brain region is the primary sleep-promoting center and which neurotransmitter does it primarily use?

The ventrolateral preoptic area (vlPOA); it uses GABA to inhibit wake-promoting arousal systems.

What role does orexin (hypocretin) play in the sleep/wake flip-flop?

It acts as the switch that stabilizes the flip-flop in the 'awake' state by exciting the arousal systems and preventing sudden, unintended transitions to sleep.

Where is the primary biological clock (SCN) located?

In the hypothalamus, situated directly atop the optic chiasm.

How does light reach the Suprachiasmatic Nucleus (SCN) for circadian synchronization?

Via the retinohypothalamic pathway, which uses a special class of retinal ganglion cells containing the photopigment melanopsin, rather than traditional rods or cones.

Identify the gene mutations associated with Advanced and Delayed sleep phase syndromes.

Advanced sleep phase syndrome is linked to a mutation in the $per2$ gene; Delayed sleep phase syndrome is possibly caused by a mutation in the $per3$ gene.

What is the function of the pineal gland and melatonin in biological rhythms?

The pineal gland secretes melatonin at night to control seasonal rhythms (day-length) and support circadian synchronization.

Which arousal system peaks with alertness and emergency states and is located in the locus coeruleus?

Norepinephrine (NE).

What does the 'rebound phenomenon' describe in the context of REM sleep?

The increased frequency or intensity of REM sleep seen after a period of REM deprivation, as the brain attempts to compensate for lost stages.

What is unihemispheric sleep and in which species is it observed?

A state where the two cerebral hemispheres sleep independently at different times; seen in bottlenose dolphins, porpoises, and some birds like mallard ducks.