The Role of the Amygdala

Question 1

What was the first evidence that the amygdala was involved in fear?

Answer 1

Kluver-bucy syndrome - disorder that occurs when both the right and left medial temporal lobes of the brain malfunction - led to little or no fear response

Question 2

What happened in patients with Kluver bucy syndrome?

Answer 2

Little or no fear response
oral or tactile exploratory behaviour
hyper sexuality
bulimia
memory disorders
inability to recognise objects
inability to recognise faces

Question 3

What happened to monkeys?

Answer 3

Bilateral removal of the temporal lobes - lack of fear response shown

Question 4

Case study of patient in NY - SM

Answer 4

Had very specific bilateral amygdala lesions as a result of a disease. Looked at her response to fearful stimuli, went to a scary place around halloween and showed her scary clips. She had flattened fear response, showed no fear and on the trait anxiety questionnaire, had a very small fear response

Question 5

Where is the amygdala?

Answer 5

Found in the temporal lobes

Question 6

What is the structure of the amygdala?

Answer 6

22 separate nuclei - lots of neurons with different characteristics

Question 7

What happens during public speaking to people with social anxiety?

Answer 7

They are more anxious than controls when talking in private, this increases if it is a public event

the amygdala is increased during public speaking

Question 8

What happens when seeing fearful stimuli?

Answer 8

Activation of the amygdala

Question 9

How does conditioning lead to fear?

Answer 9

Association of a neutral stimulus with a fear inducing stimulus leads to the neutral stimulus becoming fearful

Question 10

What binds to the amygdala a lot?

Answer 10

Lots of BZD binding sites - injection of BZD into amygdala induces anxiolytic effects, injections of a BZD antagonist polishes anxiolytic effect

Question 11

What happens if the amygdala is destroyed?

Answer 11

BZD still retain some anxiolytic effect

Question 12

What is fear compared with anxiety?

Answer 12

Fear is a normal response to threat, anxiety is unwarranted or innappropriate fear or stress

Question 13

Types of anxiety disorders and symptoms

Answer 13

PTSD
Panic disorder
Generalised anxiety disorder
Phobias 
OCD
emotional symptoms - fear
cognitive - anxious thoughts
somatic - increased heart rate

Question 14

What does it mean that there are many different anxiety disorders?

Answer 14

Points to different brain areas being involved in specific responses

Question 15

What does the amygdala excite?

Answer 15

The locus coeruleus and the hypothalamus - then get a stress response

Question 16

What is the HPA axis?

Answer 16

Hypothalamus releases CRH
Pituatary releases ACTH
Adrenal cortex releases cortisol and adrenaline

Question 17

What happens beyond the amygdala?

Answer 17

Sensory info goes to amygdala
Amygdala excites LC and hypothalamus
HPA axis
LC releases noradrenaline
flight or fight response

Question 18

What does your brain do to prepare you to deal with fear?

Answer 18

Fight, flight or freeze

Sympathetic nervous system:
increased heart rate, blood pressure, blood goes to muscles, deep fast breathing, inhibited digestion

Central nervous system: behavioural arrest, narrowing of attention, behavioural arousal, startle, cortical activation, emotional response