Human Phys Chapter 8

What does an EEG measure, and what do amplitude and frequency represent?

An EEG measures electrical activity in the brain. Amplitude represents the strength of brain signals, while frequency represents the speed of oscillations.

Define circadian rhythm and identify the role of the SCN of the hypothalamus.

Circadian rhythm is the body's internal clock regulating sleep-wake cycles. The suprachiasmatic nucleus (SCN) controls wakefulness by influencing melatonin release and other signals.

Where is orexin produced, and what is its role in wakefulness?

Orexin is produced in the hypothalamus and promotes wakefulness by stimulating brain regions associated with alertness.

What is the reticular activating system (RAS), and how does it maintain wakefulness?

The RAS is a network in the brainstem that regulates wakefulness using neurotransmitters like norepinephrine, dopamine, serotonin, and histamine.

What EEG rhythms are seen during wakefulness?

Beta (active thinking) and alpha (relaxed but awake) waves.

How does the VLPO of the hypothalamus contribute to sleep?

The ventrolateral preoptic nucleus (VLPO) inhibits wake-promoting neurons, facilitating sleep.

What is the role of the pineal gland in sleep?

The pineal gland produces melatonin, which promotes sleepiness.

How does the RAS contribute to sleep?

The RAS reduces activity in sleep by decreasing norepinephrine and serotonin levels.

What are the phases of sleep, and what EEG patterns are present?

NREM 1: Light sleep, theta waves; NREM 2: Deeper sleep, sleep spindles & K-complexes; NREM 3: Deep sleep, delta waves; REM: Dreaming, beta-like waves.

What are the physiological reasons for sleep?

Restoration, memory consolidation, immune function, energy conservation.

How does a person transition between wakefulness and sleep?

The SCN, VLPO, RAS, orexin, and neurotransmitters regulate the shift between wake and sleep states.

What is the limbic system, and what behaviors is it involved in?

The limbic system is a network of brain structures controlling emotion, motivation, and memory.

Define motivation and differentiate intrinsic vs. extrinsic motivation.

Motivation is the drive to act. Intrinsic: Internal rewards (e.g., enjoyment), Extrinsic: External rewards (e.g., money).

What is dopamine’s role in motivation and reward?

Dopamine in the mesolimbic pathway reinforces rewarding behaviors.

Define learning.

Learning is the process of acquiring new knowledge or skills.

Differentiate declarative vs. procedural memory.

Declarative: Facts and events (e.g., remembering a date), Procedural: Skills and habits (e.g., riding a bike).

Differentiate short-term vs. long-term memory.

Short-term: Temporary storage (~seconds to minutes), Long-term: Permanent storage after consolidation.

What are the roles of the hippocampus and prefrontal cortex in memory?

Hippocampus: Formation of declarative memories; Prefrontal cortex: Memory retrieval and decision-making.

What is memory consolidation, and how does long-term potentiation (LTP) contribute?

Memory consolidation is the strengthening of memories over time. LTP enhances synaptic strength, making memories more stable.