Deck 20: Learning About Danger: the Neurobiology of Fear Memories

Question 1

Behavioral systems are specialized, and each has its own neural components.

Answer 1

True

Question 2

Fleeing is the dominant and most effective defensive behavior in rodents.

Answer 2

False

Question 3

Freezing is the dominant and most effective defensive behavior in rodents.

Answer 3

False

Question 4

According to the predatory imminence hypothesis, when the prey spots a predator at a distance, its first response will be to flee.

Question 5

Learning and memory processes provide the primary way to link stimuli to the neural systems that support fear behavior.

Question 6

Caroline and Robert Blanchard found that human defensive behavior resembles that observed in animal models.

Question 7

The periaqueductal gray (PAG) produces freezing and analgesia.

Question 8

The ITC-b cluster normally excites central amygdala neurons.

Question 9

The inhibitory neurotransmitter GABA, released by ITCs, increase defensive behaviors.

Question 10

Extinction neurons project to ITC-b cells.

Question 11

To generate fear behavior, the neurons in the central amygdala must be depolarized.

Question 12

Inactivating prelimbic neurons does not affect the expression of fear behaviors.

Question 13

Mark Bouton's research found evidence against the associative loss hypothesis.

Question 14

Mark Bouton's research found evidence that extinction produces new learning.

Question 15

The fundamental outcome produced by extinction training is to change synaptic connections that will increase inhibitory control over neurons in the central amygdala.

Question 16

Spontaneous recovery could be the result of intrinsic mechanisms that produce forgetting.

Question 17

Preventing AMPA receptor endocytosis can prevent spontaneous recovery.

Question 18

Injecting an enzyme that degrades the perineuronal net into the BLA prior to or after fear conditioning erases the fear memory in adult rodents.

Question 19

If the partial NMDA agonist DCS is injected either before or immediately after extinction training, the next day the rodents display reduced extinction.

Question 20

APV and the selective GluN2B antagonist ifenprodil enhances the extinction of the fear response.

Question 21

In infant rats younger than three weeks, extinction seems to erase some aspect of the fear memory.

Question 22

Why are behavioral systems necessary?

Question 23

Briefly describe the contributions of Robert Bolles.

Question 24

Which brain structures are responsible for generating fear behaviors?

Question 25

What is the evidence that midbrain subcortical nuclei are responsible for generating fear behaviors?

Question 26

Which three components of the amygdala are relevant to the fear system?

Question 27

Describe the neural components of the fear system in as much detail as possible.

Question 28

What are the differences between the subcortical pathway and the cortical pathway? Which one provides richer representations of the experience?

Question 29

Where are clusters of intercalated cells (ITCs) located?

Question 30

The basal nucleus contains two types of neurons. What are they and what are their respective functions?

Question 31

Neurons in the prelimbic region are reciprocally connected to fear neurons in the basal nucleus to amplify the fear signal. What is the evidence for this statement?

Question 32

Which brain region can serve to amplify the fear signal?

Question 33

In the context of neurobiology, provide the meaning of extinction?

Question 34

What three observations support the belief that extinction produces new learning?

Question 35

The CS-noUS association can be thought of as a reconfigured fear circuit that allows the extinguished CS to suppress the central amygdala. Explain this assertion.

Question 36

Consider this statement: Synaptic changes that depend on NMDA receptors play a central role in the new learning that produces extinction. Defend this statement.

Question 37

D-cycloserine (DCS) is an agonist for the NMDA glycine site. When it is given before or after extinction training, it facilitates the processes that produce extinction. How was it used therapeutically in people with acrophobia? What were the results?

Question 38

What are perineuronal nets?

Question 39

How are perineuronal nets connected to fear extinction?

Question 40

What is the evidence that perineuronal nets support processes that protect from erasure the synapses strengthened by fear conditioning?

Question 41

_______ is the dominant and most effective defensive behavior in rodents.

Question 42

According to the predatory imminence gradient, as the predator moves within striking distance, the rat will _______.

Question 43

The defensive behavioral system can be activated by learned or _______ danger signals.

Question 44

_______ are responsible for generating fear behaviors.

Question 45

Neurons in the periaqueductal gray (PAG) produce _______ and analgesia.

Question 46

Neurons in the lateral hypothalamus (LH) produce changes in _______ responses.

Question 47

The lateral nucleus receives sensory input from the sensory thalamus, _______, and hippocampus, which provide information about the current state of the environment.

Question 48

When neurons in the central amygdala are activated, they activate neurons in the lateral hypothalamus and _______ generate fear behaviors.

Question 49

_______ neurons inhibit the fear response by activating ITC-b cells.

Question 50

The _______hypothesis assumes that extinction is due to the CS-alone presentation eliminating or erasing the original CS-US association.

Question 51

The _______ hypothesis assumes that the original CS-US association remains intact and a new association, called a CS-noUS association, is produced.

Question 52

Fear acquisition training strengthens synapses that link the CS to fear neurons, and fear extinction training strengthens synapses that link the CS to _______.

Question 53

Maren and his colleagues have observed that fear extinction is _______ specific.

Question 54

_______ support processes that protect the synapses strengthened by fear conditioning from erasure.

Question 55

According to the predatory imminence gradient, when a potential predator is at a distance the rat will most likely _______. (Select all that apply.)

A) flee.
B) freeze.
C) fight.
D) eat.
E) do nothing.

Question 56

Which physiological changes can be caused by a danger signal? (Select all that apply.)

A) Increase in heart rate
B) Analgesia
C) Enhanced memory
D) Erasure of fear memory
E) None of the above

Question 57

Which statement(s) is/are false? (Select all that apply.)

A) The lateral hypothalamus is responsible for changes in heart rate.
B) The periaqueductal gray is associated with analgesia.
C) The thalamus directly connects sensory information with the midbrain.
D) The neurotransmitter GABA excites neurons in the central amygdala.
E) intercalated interneurons are excitatory

Question 58

Which statement(s) is/are true? (Select all that apply.)

A) Extinction neurons project to ITC-b cells.
B) The central nucleus inhibits neurons in the midbrain.
C) Fear neurons excite neurons in the central nucleus.
D) Fear neurons excite neurons in the prelimbic region.
E) None of the above

Question 59

Which statement(s) about the neural circuit established by extinction is/are true? (Select all that apply.)

A) Excitatory projections from the extinction neurons to the ITC-b cluster are strengthened.
B) Neurons in the central amygdala will be inhibited by the CS.
C) Synaptic connections linking neurons in the lateral nucleus to fear neurons are weakened.
D) Sensory inputs representing the CS excite neurons in the central nucleus.
E) None of the above

Question 60

The region(s) of the amygdala that most directly control(s) defensive responses is the _______. (Select all that apply.)

A) lateral amygdala.
B) basal amygdala.
C) intercalated neuron region.
D) central region.
E) None of the above.

Question 61

Which statement(s) is/are false? (Select all that apply.)

A) Perineuronal nets emerge in rats around three weeks after birth.
B) Extinction will erase the fear associations if perineuronal nets are degraded after acquisition training.
C) Extinction will erase the fear associations if perineuronal nets are degraded before acquisition training.
D) Extinction training erases fear association in rats less than three weeks old.
E) None of the above.