Task 2 - Brain & Emotion

Question 1

Darwin’s view on emotion

Answer 1

1. Human emotions are homologises to those of animals
   - many emotional expressions in humans are vestigial
2. Limited set of basic emotions present across all species (anger, fear, surprise, sadness)

—> research in animals to understand human emotions

Question 2

James-Lange theory of emotion

Answer 2

-Emotions = bodily responses to emotional stimuli

Bodily response —> subjective experience

Theory has remained influential

Main contribution: emphasis on embodiement of emotions

Question 3

Cannon-bard theory of emotion

Answer 3

Hypothalamus involved in emotional response to stimuli

• responses can be inhibited by neocorticak regions

Question 4

Papez circuit

Answer 4

• sensory messages (emotional stimuli) arrive at thalamus
  —> directed to cortex (stream if thinking) and hypothalamus (stream of feeling)

Cingulate cortex integrates signals from hypothalamus and sensory cortex —> emotional experience

Top-down control:
Cingulate cortex—> hippocampus —> hypothalamus

Question 5

Klüver-Bucy Syndrome

Answer 5

Removal of temporal cortices in monkeys extinguishes emotional responses to stimuli

—> temporal lobes crucial for emotions

Question 6

MacLeans limbic system

Answer 6

• broadly supported

Hippocampus seen as core structure of the limbic system
- receives sensory input from outside world + information from internal body state

• integrate external and internal information streams —> emotional experience

Question 7

The Amygdala

Answer 7

Removal —> Klüver-Bucy syndrome

• key role in processing social signals of emotion (especially threat related, fear), emotional conditioning (fear conditioning & extinction) & emotional memory consolidation

Question 8

Amygdala & fear conditioning

Fast vs slow response

Answer 8

Two afferent routes mediate conditioning

1. Thalamo-amygdala route
   —> process crude sensory aspects of incoming stimuli
   - early conditioned fear response
2. Thalamo-cortico-amygdala route
   —> more complex analysis of incoming stimuli
   -slower conditioned emotional response

Question 9

PFC

• OFC
• PFC& Amygdala
• PFC &ACC
• PFC & bodily signals

Answer 9

OFC —> learning emotional and motivational value of stimuli

PFC&Amygdala —> learn & represent relationship between primary and secondary reinforcers

PFC & ACC —> send bias signals to other brain regions
-top down control

PFC&Bodily signals —> somatic marker hypothesis (VLPFC)
- Physiological reactions that tag previous emotionally significant events

Question 10

ACC

Answer 10

• integrates visceral, attentional & emotional information
  —> regulation of affect (top-down)
• key substrate for conscious emotional experience

Dorsal cognitive subdivision

Ventral affective subdivision —> activated by emotional stimuli
- monitors conflict between internal state and new information that might have affective or ,motivational consequences

Question 11

Hypothalamus

Answer 11

Rewarding stimuli —> sex, hunger

Question 12

Single system models

Answer 12

Cannon, Papez, MacLean

Question 13

Dual system models

Answer 13

Davidson’s valence asymmetry model

-activation/inhibition

Question 14

Multiple systems models

Answer 14

Darwin

—> different emotions underpinned by separate brain regions

Question 15

Traditional fear circuit view

Answer 15

Threat—> sensory system —> fear circuit —> fear response (defensive behaviour, physiological responses & conscious experience)

Question 16

Two system model of fear

Answer 16

Fear= product of cortical cognitive circuits (WM)

Subcortical circuits —> control defensive behaviour & physiological responses (contribute indirectly to conscious experience of fear)

Emotional & non-emotional states of consciousness arise from the same systems

Anxiety —> distant/ abstract threat

BNST = hub for anxiety
—> extended survival circuit

Amygdala = hub of fear circuit (downregulated by MPFC in healthy subjects)

NAcc —> defensive actions

Question 17

Do responses to threat and subjective fear arise from the same area (Amygdala)?

Why not?

Answer 17

1) subjective fear and anxiety do not correlate well with physiological/behavioural responses
2) patients with amygdala damage still feel fear, panic and pain

3’ threats trigger amygdala activity and physiological responses even if subjects remain unaware

4) blindsight: threat induce pd amygdala activity & defensive behaviour even in absence of conscious awareness

Amygdala —> Responsible for detecting and responding to immediate threats, but not for producing subjective feelings of fear –> It is not innate fear center

Question 18

Emergence of conscious experience

Answer 18

Subjective feeling of Fear & anxiety underlies same circuits as any other form of conscious experience –> Higher-order cortical regions

1. Global workspace theory
2. Higher-order theory (prefrontal hub)

—> separate circuits for conscious feeling and response control
–> Amygdala contributes indirectly to subjective feelings –> One interprets the bodily signals and integrates these signals with context information

Question 19

Classical fear conditioning

Answer 19

Neutral stimulus repeatedly paired with aversive stimulus Which elicits autonomic fear response

• activity in ACC, anterior insula, amygdala —> aversive conditioning network

–> After some time the person habituates and the activity in the amygdala decreases

Question 20

Extinction of conditioned fear response

Answer 20

Neutral stimulus repeatedly presented without aversive stimulus —> conditioned fear response gradually eliminated

• involves aversive conditioning network
  + prefrontal regions (regulate amygdala fear reaction)

Question 21

Symptom provocation paradigm

Answer 21

Contrast negative emotional condition with neutral condition

—> hyperactivity of amygdala during symptom provocation
- codes salience/relevance/value

Enhanced activation of fear network:

Insula: subjective feelings & interoceptive awareness

ACC: approach/avoidance, fear learning

Question 22

PTSD (neuroimaging)

Answer 22

Amgygdala hyperactivity —> elevated fear response

Hypoactivity jn mPFC and ACC —> impaired top-down control

Reduced hippocampal activity —> difficulties in defining safe contexts

Structural changes in hippocampus, amygdala and mPFC

Question 23

OCD (neuroimaging)

Answer 23

Striatal dysfunction

Hyperactive amygdala & insufficient top-down control

Hyperactive OFC and ACC