Lecture 2- The Amygdala Complex

Question 1

What is the Amygdala

Answer 1

Collection of nuclei

lateral, central and basal

Question 2

Location of Amygdala

Answer 2

Anterior portion of temporal lobe
Deep to uncus of parahyppocampus
Anterior to pez hippocampus and temporal horn of lateral ventricle

Question 3

Subdivisions of Amygdala

Answer 3

Accessory basal nucleus
Basal nucleus (magnocellular and intermediate divisions)
Basal nucleus (parvicellular division)
Medial nucleus
Central nucleus
Lateral nucleus
Paraleminar nucleus
Perlamygdaloid cortex

Question 4

Amygdaloid nuclear complex function

Answer 4

Receives integrated sensory info from higher cortical centres
Provides details to help identify objects

Question 5

Amygdaloid nuclear complex connections

Answer 5

Hippocampus (direct and indirect via entorhinal cortex)
Hypothalamus
Ventral tegmental area 
Orbital prefrontal cortex
Septal nucleus/ nucleus accumbens

Question 6

Efferent projections of Amygdaloid nuclear complex

Answer 6

Stria terminalis (arches dorsally to terminate in hypothalamus, thalamus and nuclear accumbens)
Vertical projection of fibres to septal nucleus, orbital PFC, hypothalamus and thalamus

Question 7

Subcortical inputs

Answer 7

Ventral striatum
Hypothalamus
Dorsal thalamus
Dopaminergic brainstem

Question 8

Subcortical outputs

Answer 8

Ventral striatum and basal forebrain
Hypothalamus
Midbrain tegmentum
Autonomic brainstem

Question 9

Corpus striatum

Answer 9

Projections mainly with ventral striatopallidal complex
Ventral pallidum projects to dorsal thalamus, and then onto prefrontal
cortex= provides a pathway with which amygdala can interact
with the prefrontal cortex

Question 10

Connection of amygdala to basal forebrain

Answer 10

Strong reciprocal connectivity
Via this connection, amygdala can
influence activity of neurons in neocortex

Question 11

Dorsal thalamus

Answer 11

Another pathway to effect cortical activity
Receives from:
- midline thalamic nuclei (gustatory)
- posterior group of thalamic nuclei (vision, touch and hearing)
The input of sensory stimuli for amygdala processing

Question 12

Connection of amygdala to hypothalamus

Answer 12

Major projection to bed nucleus of stria terminalis (BNST)

Also to medial and lateral hypothalamus

Question 13

Connections of amygdala with hippocampal formation

Answer 13

Major connections are with entorhinal cortex

Also hippocampus proper & subiculum

Question 14

Corticomedial nucleus afferent

Answer 14

From olfactory bulb and olfactory cortex

Question 15

Corticomedial nucleus efferent

Answer 15

To ventromedial nucleus of hypothalamus

Question 16

Corticomedial nucleus function

Answer 16

Behaviour associated with hunger and eating

Question 17

Basolateral nucleus connections (reciprocally)

Answer 17

Connected to sensory association cortical areas

Question 18

Basolateral nucleus efferent

Answer 18

To medial dorsal nuclei of thalamus, basal nucleus of Meynart and ventral striatum

Question 19

Basolateral nucleus functions

Answer 19

Behaviour associated with hunger and drinking
Behavioural reaction to stressful situations
Autonomic and somatic reflex activity

Question 20

Central nucleus connections

Answer 20

Reciprocally connected to visceral sensory and autonomic nuclei in brainstem

Question 21

Central nucleus funtions

Answer 21

Respiratory and cardiovascular responses

Question 22

Amygdala functions

Answer 22

Activating 3 components

• Recruits appropriate autonomic and endorcrine responses (via hypoth)
• reaffirms emotional significance (Via hippocamp)
• Creates memory of event (via sensory assoc ctxs and HF)

Improves efficiency of response learned over time
Forumates reactions to socially significant stimuli
Deja vu

Question 23

Hypothalamic control of ANS without Amygdala

Answer 23

Reflexive in nature
Continuous monitoring of body’s internal environment via baroreceptors and osmoreceptors and making appropriate adjustments

Question 24

Amygdaloid control of ANS

Answer 24

Mediated by instinct

Utilises prior experiences to modulate ANS activity

Question 25

Lesion of the Amygdala

Answer 25

Kluver-Bucy syndrome

• lack of fear and anger in previously wild animals
• docility
• changes in feeding behaviour
• hypersexuality
• excessive oral curiosity
• visual agnosia