The Emotional Brain

Question 1

According to LeDoux (1996) devoid of emotion we are…

Answer 1

“souls on ice”

Question 2

Where does fear originate from?

Answer 2

amygdala, in the medial temporal lobe of the brain

Question 3

What is the history of the limbic system?

Answer 3

Broca (1878) - grand lobe limbique
Papez (1937) - limbic system - a large subcortical neural circuit mediating emotion
MacLean (1952) - triune brain - evolutionary elaboration of Papez

Question 4

What are the flaws of the limbic system?

Answer 4

Unlikely one system for all emotions
it is more involved in memory than emotion
some key structures are absent

Question 5

Why should we study fear?

Answer 5

it’s similar in humans and animals
well defined experimental paradigms available to study fear
disorders of fear lie at the core of many psychopathlogies

Question 6

What is fear?

Answer 6

a response to threatening stimuli and/or situations (adaptive)

Question 7

When does fear become maladaptive?

Answer 7

when it becomes exaggerated or begins to occur in inappropriate situations

Question 8

How many annual psychiatric referrals are related to fear?

Answer 8

50%

Question 9

What are fear responses?

Answer 9

hard-wired reactions to a threat
adaptive physiological changes
readily elicited by danger stimuli

Question 10

Different types of fear response…

Answer 10

behaviour 
perceptual
reflexive
endocrine
(all unconditioned)

Question 11

Why a so few behavioural paradigms suitable for neural systems analysis?

Answer 11

the fear stimulus is poorly defined and the response is innate and so less relevant to human fears which are acquired through experience

Question 12

What are two examples of classical fear conditioning?

Answer 12

Watson and Rayner (1920) Little Albert

Pavlov (1927) defensive conditioning

Question 13

What does classical fear conditioning involve?

Answer 13

the coupling of new stimuli to pre-existing defence responses

Question 14

What must fear conditioning involve?

Answer 14

an association between the CS and US…intersection within the brain of the pathways transmitting information about the two stimuli

Question 15

What is the auditory pathway?

Answer 15

sound - cochlea - cochlea nucleas - inferior colliculus - medial geniculate - auditory cortex

Question 16

What has lesion studies shown?

Answer 16

Lesion to auditory midbrain or auditory thalamus impair simple fear conditioning but lesion to auditory cortex do not

Question 17

What are anatomical tracing studies?

Answer 17

Anterograde tracing is a technique to plot efferent projections of auditory thalamus

Question 18

How are anatomical tracing studies performed?

Answer 18

Tracer is injected into auditory thalamus - transported along axons to terminals
terminals are found in the subcortical amygdala and auditory cortex

Question 19

What do anatomical tracing studies show us?

Answer 19

Thalamo-amygdala connections prevent fear conditioning

Question 20

Where does the auditory thalamus project to?

Answer 20

lateral amygdaloid nucelus

Question 21

What types of lesions prevent fear conditioning?

Answer 21

lesions to the lateral amygdaloid nucleus (LA)

Question 22

What is the lateral amygdalaoid nucleus?

Answer 22

the input system of the amygdala

Question 23

Where does the lateral amygdaloid nucleus project to?

Answer 23

central nucleus of the amygdala (directly and indirectly)

Question 24

What do central nucleus lesions prevent?

Answer 24

expression of conditioned fear responses

Question 25

Where does the central nucleus of the amygdala project to?

Answer 25

areas individually controlling components of the fear response in the hypothalamus and midbrain

Question 26

what is the central nucleus of the amygdala?

Answer 26

the output system

Question 27

What are the two fear pathways?

Answer 27

direct thalamo-amygdala pathway

indirect thalamo-cortico-amygdala pathway

Question 28

What does the thalami-amygdala pathway allow for?

Answer 28

fast response to potential danger

Question 29

What does the thalamo-cortico-amygdala pathway allow for?

Answer 29

recognition and elboration

Question 30

Why do we have the thalamo-cortico-amygdala pathway?

Answer 30

Better to make a false positive response than a false negative response in terms of survival

Question 31

At a cellular level learning is mediated by…

Answer 31

mechanisms such as long-term-potentiation (LTP)

Question 32

What does LTP involve?

Answer 32

occurs in the lateral amygdala and involves cooperativity between different inputs at synapse

Question 33

What mediates LTP?

Answer 33

glutamate acting sequentially at non-NMDA receptors (partial depolarisation) and at NMDA receptors (full depolarisation)

Question 34

What is LTP a mechanism for?

Answer 34

converging inputs to lateral amygdaloid nucleus resulting in memory formation

Question 35

What does an injection of NMDA to the lateral amygdala cause?

Answer 35

impaired fear conditioning

Question 36

Temporal lesions in primates cause///

Answer 36

reduction in emotional responsivity (Kluver and Bucy, 1937)

Question 37

Kalin et al 2004 said the amygdala in rhesus monkeys…

Answer 37

plays a major role in mediating fear and anxiety

Question 38

fMRIs show amygdala activation…

Answer 38

in response to visual and vocal fear stimuli

Question 39

patients with bilateral amygdala damage…

Answer 39

are impaired in recognition of fear stimuli

Question 40

in cortically blind patients…

Answer 40

fear conditioning to a visual cue is intact

Question 41

patients with amygdala damage show…

Answer 41

selective impairment in long term memory for emotional material

Question 42

activity of amygdala correlates highly with?

Answer 42

recall of emotionally charged material

Question 43

Neuroimaging shows dysfunction of the amygdala in;

Answer 43

social and animal phobias
panic disorders
PTD
GAD