W8 - Fear 2/2

Question 1

What is LeDoux’s Two-System Model? What is the alternative model?

Answer 1

LeDoux’s Two-System Model = defensive survival circuit + cognitive circuit in parallel

Fear Center Model = fear -> defensive behaviour and physiological responses

Question 2

What was the conclusion of Lashley in his search for engrams? Why?

Answer 2

‘engrams’, are not localized in a specific part of the brain -> memory is more disrupted by the extent of the lesion than by the location of the lesion

Question 3

What is the difference between MRI and fMRI?

Answer 3

MRI = structural measures
fMRI = functional (activity) measure

Question 4

What physiological measure can be used to assess conditioned fear response?

Answer 4

Skin conductance (indirect measure of sympathetic autonomic activity = arousal)

Question 5

What is a fear conditioning retention measure?

Answer 5

fear conditioned stimuli selectively not presented during extinction learning

Question 6

What did Hen et al. report for changes in connectivity during extinction learning for CS+ and CS-? During fear conditioning?

Answer 6

Extinction learning-induced changes in brain connectivity are specific to a CS+, and connectivity related to CS+ increased steadily over course of extinction learning (early -> late)

In late conditioning, CS+ connectivity was lower than CS- connectivity, this is opposite what was observed for extinction ^^

Question 7

What did Hen et al. report for changes in activity during extinction learning for CS+ and CS-? During fear conditioning?

Answer 7

Early in conditioning, there is increased overall activity in extinction-associated regions for the CS+

In early extinction, this activity further increases & is elevated again during extinction recall

Question 8

How are relating connectivity and activity in fear extinction according to the data of Hen. et al.?

Answer 8

The activity results suggest that modulation of brain activation mainly occurred during early extinction and extinction recall, whereas, connectivity changes were more prominent in late extinction

SOT there is a dissociation between changes in connectivity and activity

Question 9

The extinction retention index (ERI) used in Hen. et al. was dependent on which measure?

Answer 9

skin conductance response

Question 10

Connectivity or anxiety correlates with extinction (ERI)? What does that suggest?

Answer 10

Connectivity, not activity

This suggests that changes in connectivity, rather than activity, may be more relevant to understanding extinction

Question 11

True or false: Changes in activity during extinction learning predict extinction memory recall the next day

Answer 11

False: Changes in connectivity during extinction learning predict extinction memory recall the next day