Lecture 15 - Sleep Flashcards
What is a sleep laboratory?
A sleep laboratory is a controlled environment where researchers monitor a person’s brain and body activity during sleep studies.
How is brain activity measured during sleep?
Brain activity is measured using an EEG (Electroencephalogram), where electrodes are placed on the scalp to capture different types of brain waves associated with various sleep stages.
What does an EMG measure in a sleep study?
An EMG (Electromyogram) measures muscle activity by placing electrodes on the chin, helping to determine when muscles relax during sleep.
What is the purpose of an EOG in sleep research?
An EOG (Electro-oculogram) tracks eye movements using electrodes near the eyes, which are particularly noticeable during certain sleep stages, like REM sleep.
What are beta waves and when are they observed?
Beta waves (13-30 Hz) are brainwave patterns that occur when a person is awake, alert, and actively engaged in cognitive tasks. They are characterized by high frequency (fast brain activity) and low amplitude (small fluctuations in the electrical signals), which means the brain is processing information with quick, scattered activity. Essentially, beta waves reflect a state of heightened mental focus and activity.
What do alpha waves indicate about a person’s state?
Alpha waves (8-13 Hz) indicate a relaxed, awake state, such as when someone is quietly resting with their eyes closed.
When do theta waves typically occur?
Theta waves (4-8 Hz) appear when someone is drowsy or lightly asleep and become more prominent in the early stages of sleep.
Describe delta waves and their significance in sleep.
Delta waves, which are low-frequency (<4 Hz) and high-amplitude brain waves, occur during the deepest stages of sleep, known as slow-wave sleep. They indicate synchronized neural activity, meaning that large groups of neurons are firing together in a coordinated way. Delta waves are important for restorative sleep, aiding in physical recovery and memory consolidation.
What characterizes REM sleep?
REM sleep (Rapid Eye Movement sleep) is a stage of sleep marked by desynchronized brain activity, which resembles the brain’s activity when we’re awake. During this phase, we experience rapid eye movements, vivid dreams, and muscle paralysis (which prevents us from acting out our dreams). Despite being asleep, the brain is highly active and uses a lot of oxygen, similar to when we’re awake.
How does the EEG pattern change during slow-wave sleep?
During slow-wave sleep, which occurs in stages 3 and 4 of non-REM sleep, the EEG (electroencephalogram) shows large amplitude, low-frequency waves. This pattern reflects synchronized neuronal activity—where groups of neurons fire together—resulting in low brain metabolic activity. This stage of sleep is considered the most restorative because the brain is less active and allows for physical recovery and memory consolidation.
What happens to muscle tone during REM sleep?
During REM sleep, muscle activity drops significantly, causing muscles to become limp, which can lead to animals falling off surfaces if they sleep on narrow platforms.
What effects does prolonged sleep deprivation have on rats?
Prolonged sleep deprivation in rats, achieved by preventing sleep using EEG detection (which monitors brain activity), causes problems with regulating body temperature and metabolism, leading to weight loss, serious health issues, and eventually death after two to three weeks.
What are some effects of not getting enough sleep?
Effects of sleep deprivation include feeling tired and sluggish, mental decline, poor reactions and judgment, mood and behavior issues, memory and learning problems, health risks, sleep debt, and microsleeps.
What is sleep debt?
Sleep debt is the accumulated amount of sleep loss that the body needs to repay by sleeping more later, typically occurring when sleep is missed.
How does lack of sleep impact your mood and behavior?
Lack of sleep raises stress hormones, leading to increased moodiness, impulsiveness, and emotional swings.
What are microsleeps, and what happens during them?
Microsleeps are brief periods of sleep lasting a few seconds that occur when someone is extremely sleep-deprived, during which they may become unaware of their surroundings.
Why is sleep critical for survival?
Sleep is vital for physical and mental health, aiding in cognitive functions, emotional stability, memory consolidation, and overall well-being.
How do dolphins sleep differently from humans?
Dolphins sleep by having one half of their brain sleep at a time, allowing them to remain somewhat alert and aware of their surroundings.
How much sleep do newborns typically need compared to adults?
Newborns sleep about 16 hours a day, equally dividing their time between REM and NREM sleep, while adults average about 7 hours, spending most of that time in NREM sleep.
How does sleep duration vary between predator and prey animals?
Predators tend to sleep longer and more uninterrupted, while prey animals usually sleep in short bursts to remain vigilant.
What is the general relationship between animal size and sleep duration?
Smaller animals tend to sleep more than larger animals, indicating that species with lower body weight usually have longer sleep durations.
How does metabolic rate relate to body weight in animals?
Larger animals have a higher total metabolic rate because they have more cells and larger organs, meaning they burn more energy overall. However, on a per-cell basis, their metabolic rate is lower compared to smaller animals. This is because smaller animals have a higher surface area-to-volume ratio, which leads to more heat loss and requires their cells to burn more energy to maintain body temperature. In short, larger animals use more energy overall, but their cells use less energy individually than those of smaller animals.
How does body size influence sleep patterns and behaviors in animals?
Larger animals tend to have slower metabolism, longer lifespans, less sleep overall, and longer sleep cycles, which suggests an evolutionary advantage in energy efficiency.
What is a possible hypothesis for the connection between body size and sleep duration?
The hypothesis suggests that larger body sizes provide advantages like better heat retention and efficient nutrient and waste distribution, leading to reduced cellular work and, consequently, less need for sleep.
How might sleep serve a restorative purpose for the body?
Since total sleep time is linked to metabolic functions and energy efficiency, it suggests that sleep is essential for restoring or recharging the body’s systems.
What is one main theory about why sleep is important for recovery?
The recovery theory suggests that sleep helps us recover from physical activity or mental effort, implying that individuals who exert themselves physically or mentally should need more sleep.
Why do people who exercise or are restricted in movement not necessarily sleep more?
Evidence shows that increased physical activity or being restricted in movement does not lead to a significant increase in sleep duration, contradicting the recovery theory.
What small physical changes occur in the body during sleep?
During sleep, the heart rate and blood pressure slightly decrease, but the body’s energy usage doesn’t drop drastically compared to when it’s simply at rest while awake.
How does sleep relate to brain processing, learning, and memory?
Sleep may allow the brain to reorganize and save memories, facilitating better memory retention and processing that is challenging to achieve while awake.
