Sleep and Mental Wellbeing Review

Comprehensive flashcards covering consciousness, sleep measurement (EEG, EMG, EOG), sleep cycles, biological rhythms, developmental changes in sleep, sleep deprivation, and sleep hygiene based on lecture notes.

How is consciousness defined in the study of mental processes?

Consciousness is the awareness of your own internal mental processes, including thoughts, feelings, sensations, and perceptions, plus your awareness of the external world around you.

What is the difference between a naturally occurring and an induced altered state of consciousness (ASC)?

A naturally occurring ASC occurs without the need for any aid (e.g., sleep, daydreaming), whereas an induced ASC is intentionally brought on by an aid such as medication, alcohol, meditation, or hypnosis.

Why is sleep considered a psychological construct?

It is a concept that cannot be objectively observed or measured directly through the collection of data, but is widely understood to exist.

What does an electroencephalograph (EEG) detect and record?

It detects, amplifies, and records the electrical activity of the brain, specifically brain wave patterns.

In brain wave analysis, define frequency and amplitude.

Frequency refers to the number of brain waves per second ($faster = more$ waves per unit time), while amplitude refers to the intensity or size of the peaks and troughs measured in microvolts ($\mu V$).

Which brain wave pattern is associated with alertness, intensive mental activity, and REM sleep dreams?

Beta brain waves, which have the highest frequency and lowest amplitude.

What are the characteristics of Delta brain waves?

They are associated with deep, dreamless sleep or unconsciousness, and represent the lowest frequency and highest amplitude.

What is the function of Electromyography (EMG) in sleep studies?

EMG is a method used to detect, amplify, and record the electrical activity of muscles, indicating muscle tension and movement.

What does Electro-oculography (EOG) measure?

It measures eye movements and positions by detecting electrical activity in the muscles that control eye movements.

Define circadian rhythm and provide an example.

A circadian rhythm is a biological process that coordinates body system activity over a $24$ hour period, such as the daily sleep-wake cycle.

What is an ultradian rhythm?

A biological process that coordinates body activities over a period of less than $24$ hours, such as the human sleep cycle consisting of NREM and REM stages.

What is the role of the suprachiasmatic nucleus (SCN) in sleep regulation?

The SCN acts as the master body clock in the hypothalamus; it receives light info from the eyes and adjusts the pineal gland's production of melatonin to regulate the sleep-wake cycle.

How does the pineal gland respond to light and darkness?

When light is detected, the SCN inhibits the pineal gland to suppress melatonin; in darkness, the pineal gland releases melatonin to induce sleepiness.

What occurs during a complete sleep cycle and how long does it last on average?

A complete cycle consists of periods of NREM sleep (Stages $1-3$) and REM sleep, lasting approximately $90$ minutes.

Why is REM sleep often called 'paradoxical sleep'?

Internally the brain and body systems are active (high brain wave activity, irregular heart rate), but externally the body appears calm and inactive due to muscle paralysis.

How does the proportion of REM sleep change between newborns and adults?

Newborns ($0-3$ months) spend about $50\%$ of their sleep in REM, while adults spend approximately $20-25\%$ of their total sleep time in REM.

What is circadian phase delay in adolescents?

A hormonally determined shift in melatonin release to $1-2$ hours later than other age groups, leading to a preference for a later bedtime.

How do sleep patterns change in older adults compared to younger adults?

Older adults experience more fragmented sleep, an increase in sleep latency, a reduction in the amount of NREM Stage $3$ sleep, and a circadian phase advance (earlier sleep/wake times).

Define sleep debt.

The accumulated amount of sleep loss due to insufficient sleep, calculated as the difference between the sleep needed to function optimally versus the amount actually obtained.

Describe the behavioural effects of partial sleep deprivation.

Effects include impaired regulation of behavior, risk-taking, slower reaction times, reduced motor function, and microsleeps.

How does sustained wakefulness compare to Blood Alcohol Concentration (BAC) levels?

$17$ hours of full sleep deprivation is equivalent to a BAC of $0.05\%$, and $24$ hours is equivalent to a BAC of $0.10\%$.

What is Delayed Sleep Phase Syndrome (DSPS)?

A circadian rhythm sleep disorder where the major sleep episode is delayed by $2-3$ hours relative to desired sleep time, common in adolescents.

How is Bright Light Therapy (BLT) used to treat DSPS?

Light exposure occurs in the early morning ($6-8$ am) to advance the circadian rhythm to an earlier time, prompting earlier melatonin release in the evening.

Define sleep hygiene.

Sleep-related behaviors and environmental conditions that are beneficial for sleep, such as maintaining a regular schedule and associating the bed only with sleep.

What is a zeitgeber and what is the primary one for humans?

An environmental time cue that synchronizes biological rhythms; daylight (natural light) is the primary zeitgeber for the human circadian rhythm.

What impact does blue light have on melatonin and sleep?

Blue light powerfully inhibits melatonin production, keeping the individual alert and delaying sleep onset, which can lead to a circadian phase shift.

What is the recommended room temperature for optimal sleep?

The ideal room temperature is suggested to be between $17-19\,^{\circ}C$ or $19-21\,^{\circ}C$ to promote sleep onset and better quality sleep.