Amygdala

Question 1

Amygdala

Answer 1

Stimulation of particular regions (most of which interact with each other) leads to typical reactions

Question 2

Corticomedial Area =

e.g.?

Answer 2

=> Primed to Attack, prolonged inclination toward aggression

• e.g. Rabies, from a virus that attacks, especially, temporal region of brain => extreme aggression

Question 3

Lateral Nuclei =

Answer 3

> Startle Reflex Sudden loud noise => Freeze, Tense neck to protect spine, Inc heart rate

Question 4

Startle Reflex is influenced by Amygdala connections…

Answer 4

=> from Pain fibers, and Visual and Auditory input, to detect and learn negative associations

=> to Central Gray Area of Midbrain = Part of Tegmentum for motor control, esp of neck muscles

=> to Hypothalamus => Influences Autonomic NS response (e.g. inc blood pressure, heartrate, etc)
- Recall that 2 of the Hypothalamic “4 Fs” = Fighting & Fleeing

Question 5

Central & Basolateral Nuclei

Answer 5

=> Conditioned fear, via integration of sensory info (e.g. vision + pain)

• Unlearned Startle Reflex

Question 6

Unlearned Startle Reflex (e.g. loud noise > !!)

Answer 6

can be further conditioned (modified via learning)

 - If visual stim (e.g. light) is paired w/noxious stimulus (e.g. shock) light alone comes to elicit fear 
 - Once association is learned, paired signal enhances reflex (i.e. jump higher to noise if light on)

Question 7

Startle Reflex

Answer 7

enhanced by any unpleasant stimulus (e.g. disturbing photo, sound or odor) presented simultaneously, whether or not previously paired with unconditioned (noxious) stimulus

Question 8

a paired signal previously associated w/pleasant stimulus will decrease…

Answer 8

…Startle Reflex

• e.g. Light paired w/soothing warmth&raquo_space; Not jump as high to noise if light is on

Question 9

All of above aid memory of emotionally-laden stimuli, via connections to/from Hippocampus

Answer 9

• i.e. Emotion-provoking (esp aversive) images or words, if not too intense, remembered better than neutral

Question 10

shared emotion

Answer 10

Amygdala active not just when feel/express but also when observe emotion in others
- e.g. In many primates, infants learn what to fear by watching/imitating mother’s reaction

Question 11

Urbach-Wieth Disease =

Answer 11

= degenerative calcification in Amygdala, (or other damage) can lead to…

  - Impaired ability to recognize Facial Expression, especially fear and untrustworthiness 

 - Patients recognize individuals, gender, but trouble naming emotion, judging if face is “approachable” 
           - May be related to disinterest in eyes; forced to consider eyes only, judgments are a bit better 

 - Patients generally placid, do not experience strong likes/dislikes, act less timid in strange environment

Question 12

Overall, Amygdala seems particularly involved in

Answer 12

mediating critical social (e.g. aggression, mating) interactions
and learning/responding to these and other potentially threatening or exciting stimuli