The Amygdaloid Complex

Question 1

Name the 3 subgroups of the amygdaloid complex

Answer 1

Basolateral complex
Cortico-medial complex
Central nucleus

Question 2

What are the effects of a bilateral amygdaloid complex lesion in monkeys?

Answer 2

Tameness
Hypoemotionality
Hyperphagia

Question 3

What are the effects of adult-acquired bilateral amygdala lesions in humans?

Answer 3

Hypersexuality, hypoemotionality, oral tendency

Milder than Kluver-Bucy syndrome - but same symptoms

Question 4

What is the effect of electrically stimulating the amygdala in awake humans?

Answer 4

Positive and negative feelings

Question 5

Which type of neurons does the basolateral complex contain?

Answer 5

Glutamatergic

Question 6

What type of neurons do the central nuclei contain?

Answer 6

GABAergic

Question 7

The central nuclei form part of which system?

Answer 7

Autonomic

Question 8

The cortical and medial nuclei form part of which system?

Answer 8

Olfactory

Question 9

Where in the amygdala does the main olfactory bulb project to?

Answer 9

Cortical nuclei

Question 10

Where in the amygdala does the accessory olfactory bulb project to?

Answer 10

Medial nuclei

Question 11

What is the role of the medial nuclei?

Answer 11

Project to hypothalamic regions involved in affilative and defensive behaviours

Question 12

What is the role of the cortical nuclei?

Answer 12

Coordinate responses involving odour-driven innate aversive and appetitive behaviours

Question 13

The basolateral complex forms part of which system?

Answer 13

Frontotemporal system

Question 14

What is the role of the basolateral complex?

Answer 14

Integrates multimodal interoceptive and exteroceptive sensory information - mediates learning about sensory cues

Question 15

Where does the lateral nucleus receive sensory inputs from?

Answer 15

S1
Association cortices
Thalamus
Hippocampus

Question 16

Where does the lateral nucleus project to?

Answer 16

Basal and accessory basal nuclei

NAc and PFC - directly and via dorsomedial thalamus

Question 17

Where does the whole basolateral complex project to?

Answer 17

Central nucleus

Question 18

Where does the central nucleus project to?

Answer 18

Hypothalamus
Midbrain
Pons
Medulla

Question 19

What mediates CS-US association?

Answer 19

Basolateral complex

Question 20

What mediates defensive response performance (e.g. freezing, escape)?

Answer 20

Central nucleus

Question 21

What is the predominant serial view of amygdala processing?

Answer 21

Lateral -> basal -> central -> hypothalamus/brainstem

Question 22

What is Killcross and Balleine’s (2006) alternative parallel view of amygdala processing?

Answer 22

Basolateral and central nuclei work in parallel
Basolateral complex recognises cues predicting US
Central nucleus mediates affective reactions to CS - encodes prediction of future affective event - no specification of what event is

Question 23

How does a basolateral complex lesion affect Pavlovian fear conditioning to a tone in mice?

Answer 23

No association between US and CS

Does not learn to fear tone

Question 24

How does central nucleus inhibition affect Pavlovian fear conditioning to a tone in mice?

Answer 24

No freezing (fear expression)
Learning still occurs

Question 25

How do PFC inputs modulate the basolateral complex?

Answer 25

Extinguish fear conditioned response (fear extinction) | Association never removed from amygdala

Question 26

What is Urbach-Wiethe disease?

Answer 26

Progressive bilateral amygdala calcification - from young age

Question 27

How did Urbach-Wiethe disease affect Patient SM?

Answer 27

Deficits in recognising facial expression of fear No fear behaviour Increased trustworthiness of positive and negative faces Increased comfortable proximity to others

Question 28

What is a weakness of Patient SM as a case study of bilateral amygdala lesion?

Answer 28

Had facial disfigurement - may have caused decreased fear response

Question 29

How did Urbach-Wiethe disease affect South African patients and what does this suggest?

Answer 29

Decreased basolateral amygdala volume Increased fear BLA may inhibit fear behaviour

Question 30

What is the effect of an amygdala lesion in macaques and what does this suggest the role of the amygdala may be?

Answer 30

``` Social disinhibition Increased approach behaviour Increased likeability Decreased aggression Decreased social hierarchy ranking ```

Question 31

What do amygdala neurons respond to in macaques when shown photos of other macaques?

Answer 31

Some respond to identity of macaque | Some respond to specific facial responses

Question 32

What do individual amygdala neurons respond to in humans?

Answer 32

Some to selective part of face Some to whole face Some differentiate between happy and fearful expressions

Question 33

What is the overall role of the amygdala and the purpose of its function?

Answer 33

Value coding - positive and negative values | Updates values

Question 34

Name the areas of the amygdala olfactory system

Answer 34

Olfactory input - cortico-medial nuclei - hypothalamus

Question 35

Where does the main olfactory bulb project to and what is the role of the next projection in the pathway?

Answer 35

Cortical nucleus | Hypothalamus - coordinating responses about odour-driven innate aversive/appetitive behaviours

Question 36

Where does the accessory olfactory bulb project to and what is the role of the next projection in the pathway?

Answer 36

Medial nucleus | Hypothalamus - affiliative/defensive behaviours

Question 37

Name the areas of the amygdala fronto-temporal system

Answer 37

Neocortex - basolateral nuclei - dorsomedial thalamic nucleus - PFC

Question 38

Name the areas of the amygdala autonomic system

Answer 38

Visceral input - central nucleus - hypothalamus/brainstem