The Fear System

Question 1

Identify which circuit is named after Papez and which areas were added by MacLean to from the limbos system

Answer 1

• Papez: hippocampus, hypothalamus, anterior thalamus and the Cingular gyrus
• MacLean added: amygdala, orbitofrontal cortex and some portions of the basal ganglia

Question 2

How does the Morris et al experiment help identify the amygdala’s role in perceiving fear/danger?

Answer 2

• used fMRI in which participants see series of faces over a period of time (gradual shift from happy to a fearful face)
• regional cerebral blood flow is measured across the brain and correlated with the shift in expression
• the activity in the amygdala correlates highly with the pattern of change in facial expressions in the direction of fear

Question 3

Understand how the hypothalamus is a key structure in the body’s response to stress

Answer 3

• The hypothalamus triggers a chemical chain that results in the release of adrenaline and cortisol which is key to the fight-flight response
• The hypothalamus is the controlling organ

Question 4

Which structures are important for discrimination and context conditioning?

Answer 4

Don’t know

Question 5

How LeDoux’s lesioning studies identified the two pathways by which emotional learning occurs?

Answer 5

Don’t know

Question 6

Note the 6 basic emotions according to the universality of facial expressions and their meaning across cultures

Answer 6

Anger, happiness, fear, discussed, surprised and sadness