Chapter 5

Question 1

Define circadian rhythm

Answer 1

Behavioral and physiological changes in an organism that adhere to a 24-hour cycle

Question 2

Explain circadian rhythm’s role in regulating sleep

Answer 2

How much time a species allots to sleep during a 24-hour period is shaped by evolution based on feedback loops and homeostatic mechanisms regulated by melatonin 褪黑素

Question 3

Describe the human sleep cycle

Answer 3

1. NREM: Physiological processes and brain waves slow down.
2. REM: brain waves that are more similar to waking state and rapid eye movement under closed eyelids.

Question 4

features of the 5 stages of sleep

Answer 4

1. NREM Stage I: Light sleep( brain waves slow; jerky movements)
2. NREM Stage II: Light sleep( Body temperature drops, heart rate slows and eye movements stop)
3. NREM Stage III/IV: Deep sleep
4. REM Sleep Stage 5: Breathing rate goes up; experience dreams

Question 5

Describe what occurs during various sleep disorders

Answer 5

insomnia; narcolepsy: Loss of cells in the hypothalamus that produce orexins; Sleep apnea; Night terrors; Sleepwalking

Question 6

Describe and compare 3 theories of dreaming

Answer 6

1. Dream protection theory: Dreams represent wish fulfillment and a symbolic attempt to realize an unfulfilled desire.
2. Activation-Synthesis theory: Dreams reflect the brain’s attempt to make sense of random and internally generated neural signals during REM.
3. Neurocognitive Theory: Dreams are a meaningful product of our cognitive capacities.

Question 7

Describe some common myths related to hypnosis and explain 2 hypotheses that might explain what is occurring.

Answer 7

1. It produces a trance state in which “amazing” things happen.
2. It is a sleeplike state.
3. Sociocognitive theory: A person’s approach to hypnosis is based on their attitudes, beliefs, and experiences.
4. Dissociation theory: Hypnosis is based on a separation between personality functions that are normally well-integrated.

Question 8

Describe the brain’s reward system

Answer 8

consists of the interacting mesolimbic and mesocortical systems.

Question 9

Explain how drugs use can lead to addiction

Answer 9

1. Intoxication: VTA regulates NAc to increase dopamine signaling.
2. Craving: Baseline of dopamine lowered. Amygdala and PFC activation leads to craving for a substance that raised it in the first place.
3. Compulsive seeking: If “needs” are not met, the global recruitment of brain structures(PFC and the hippocampus) leads to compulsive seeking and use of the drug.

Question 10

Distinguish between different types of drugs and their effects on consciousness

Answer 10

1. Stimulants兴奋剂：rev up the CNS
2. Nicotine: stimulates VTA dopamine-producing neurons.
3. Cocaine and amphetamines: block the reuptake of dopamine
4. Depressants: lower CNS activity
5. Alcohol: facilitates GABA neurotransmission
6. Narcotics毒品：directy target reward system
7. Opioids: inhibit GABA-producing neurons.
8. Psychedelics致幻剂：lead to cravings

Question 11

Compare 3 evolutionary perspectives that contribute to explain our universal preference to consume alchohol

Answer 11

1. Social hypothesis: social bonds
2. Sanitation hypothesis
3. The “drunken monkey” hypothesis: preference for foraging ripe.