Psychobiology: Emotion theories and brain mechanisms, WEEK 8

Question 1

Emotion

Answer 1

• Not a single/simple concept
• Emotions = responses characterised by physiological change (autonomic/hormonal), behavioural response, change in cognition and subjective feelings.

Question 2

Meaning of characteristics of emotion

Answer 2

1. Physiological change = release of hormones, change in cardiovascular system (breathing) etc…
2. Behavioural response = change in behaviour
3. Change in cognition = change in way of thinking
4. Subjective feelings = what people are most aware of + what is felt

Question 3

Fear as an example of emotion

Anger + happiness (e.g too)

Answer 3

• Psychobiologists study fear as these responses can easily be studied in exp animals + are well characterised > when put in a fearful situation the following are found
  1. Change in heart rate, blood pressure, respiratory rate, pupil size (physiological change)
  2. Facial expressions, immobility, avoidable behaviour (behavioural)
  3. Enhanced attention + memory > more likely to remember fearful events or pay attention to things we are fearful of (change in cognition)
  4. Feeling of fear (subjective feeling)

Question 4

Function of emotional responses

Answer 4

• Emotions are driven by biologically significant stimuli > e.g: fear of a spider as spiders can cause danger
• Emotional responses can have adaptive benefits > can find food, water, reproduce more effectively, avoid danger, avoid conflict by signalling intent (submission) using facial exp.
• Emotional responses can be maladaptive too > too much emotion can lead to phobias, PTSD, drug addiction, non-homeostatic obesity etc…
• These responses are largely learnt > implementing a response to a certain stimulus = learnt (basis of fear conditioning)

Question 5

James-Lange Theory of Emotion

Answer 5

• Looks at relationship between biological response + subjective feeling
• James-Lange theory suggests that we feel emotions after our peripheral response > e.g. if we are afraid of snakes and there is one in front of you, you would run away (peripheral resp) and feel afraid > James-Lange theory suggests you don’t run away because you’re afraid but you running away causes you to be afraid.
• Supported by evolutionary theory as animals like sea slugs cannot feel emotions yet show fear response > if sea slug can run away w/o feeling afraid, does that mean through evolution we have placed a necessity of feeling afraid to trigger running away
• Stimulus in EV is perceived by brain which triggers peripheral response which the brain then interprets these changes which lead to subjective emotion being felt. > peripheral response being intact and interpreted causes emotion to be felt (cause + effect rel)
• There are specific patterns of changes in peripheral resp for different emotions.

Question 6

Cannon-Bard Theory of Emotion

Answer 6

• Suggests subjective emotions can precede emotional responses sometimes > not always
• If James-Lange theory was correct ^ this would not happen > Cannon believes the peripheral changes aren’t different enough to mediate the various responses
• Stimulus in EV is perceived + has a direct influence on subjective feeling + on peripheral response > change in emotional and biological state happens in parallel > no cause and effect
• Could be a slight effect of experiencing the emotion on how extreme the peripheral response
  e. g: the more afraid, the faster we run but we do not need to feel afraid to run or run to feel afraid

Question 7

Cannon-Bard vs James-Lange

Answer 7

1. JL argues visceral changes are apart of peripheral resp but CB argues visceral changes aren’t fast enough to explain how quickly we experience different emotion, different enough, sensitive enough for JL to be right > viscera = organs + feeling of a pit in your stomach or a feeling deep down
   - CB argues you either have visceral change or don’t, they aren’t sensitive enough to explain different grades of emotion (e.g. very afraid or a bit afraid)
2. James argues we could prevent experiencing subjective emotion > CB disagrees as emotions + peripheral resp happen simultaneously
3. James suggests if we stimulate a peripheral response in a specific pattern of responses for a particular emotion > an emotional feeling can be felt even in a non-emotional event > CB would disagree as peripheral change does not trigger emotion

Question 8

Schachter-Singer Theory/

Two factor theory/cognitive labelling theory

Answer 8

• Agrees w/ JL that peripheral resp triggers an emotional state but disagree that PR + its pattern determine which emotion is felt > S-S argue detection of PR tells us an emotion should be felt but not which emotion > interpretation of EV and context occurs which tells us what is happening in the external context thus what is causing the PR therefore what emotion should be felt
• This theory came from S-S 1962 study

Question 9

Schachter and Singer 1962

Answer 9

• Gave ppt novel vitamin supplement, suproxin > was actually adrenaline > informed some ppt about biological effects of vitamin supplement while other ppt weren’t informed.
• Ppt were then put in a room where an actor either behaved angrily or euphorically > ppts were asked what emotions they felt
• Ppt informed of side effects did not report any feeling of emotion > S-S argue that there is a peripheral response but the ppts interpretation is that there is an alternative cause for PR as they know it is caused by suproxin thus no emotion is felt.
• Uninformed ppt use context + the way the actor is behaving to guide interpretation process to produce appropriate emotion.
• In euphoric condition, ppt felt happy but in the angry condition they reported feeling anger
• ^ Pattern of beh cannot be explained by JL or CB but development of cog labelling explains these findings

Question 10

Translational implications of theories of emotion

Answer 10

• Relevant for reliance on lie detectors > polygraphs record peripheral resp like sweating
• We have no control over emotional resp when we lie, when we lie we cannot control emotional resp such as fear of being found out or guilty > this manifests as an emotional response
• Depending on which theory is correct, reliability of lie detectors can be supported/rejected.
• Emotions are the result of complex two way interactions between physiological state + cognitive processes.

Question 11

Brain produces emotion

Answer 11

• What mechanisms in the brain allow emotional responses to take place > emotion is regulated by the brain
• Phineas Gage > had damage to his skull in the ventral pre-frontal cortex when a tamping iron went through it > he was recovered and could walk/talk but his personality changed + showed risky behaviour often in contrast to how he was before the incident. > due to inability to use emotional cues to regulate behaviour
• Klüver-Bucy syndrome > rare syndrome in humans so was replicated in monkeys > Klüver + Bucy found removal of entire temporal lobe had many effects including emotional eff > monkeys had lack of emotion, less facial exp + vocalisations > Weisskhrantz (1958) replicated this by damaging amygdala
• suggests brain impacts emotions

Question 12

Limbic system

Answer 12

• Limbic system = brain areas underpinning emotion + other things > limbic comes from limbus = edge > structures of the limbic system found on edge of corpus callosum
• Need to look at specific areas of the brain associated w/ emotion + find evidence for it

Question 13

Amygdala: anatomy

Answer 13

• Small area deep in the brain
• Called amygdala as it is latin for almond (looks like it)
• 2 main areas of the amygdala which when its put together we can see there are pathways taking information to the amygdala > the info is then processed in amygdala
• Amygdala is localised in a place where it can coordinate outputs associated with fear + anxiety.
• Amygdala is in a good place in terms of connectivity to mediate emotion

Question 14

Stimulating amygdala

Answer 14

• Just because an area of the brain has the right connections doesn’t mean it does what we think it does > evidence supports that if the amygdala is stimulated, you get an emotional resp
• Evidence supports that if the amygdala is stimulated, you get an emotional response (in animals + humans)
• When humans have brain surgery, neurosurgeons stimulate areas of brain to see they are in the right place > when amygdala is stimulated they ask how patient is feeling > often say they feel anxious.

Question 15

Damage to the amygdala

Answer 15

• Evidence in animals w/ damage to amygdala result in timidity, tameness, change to fearful behaviour

Question 16

Evidence of damage to amygdala: Patient SM

Answer 16

• Some people w/ amygdala damage are incapable of undergoing fear conditioning > don’t show appropriate resp to stimulus (like blink or galvanic skin resp)
• Patient SM has rare Urbach Wiethe disease > causes calcium to be deposited selectively in amygdala which leads to neuronal death only in amygdala > made patient SM incapable of fear conditioning
• Feinstein et Al (2011) showed emotional film clips + tested feelings using questionnaires + scales > SM showed much lower levels of fear compared to healthy controls.
• Feinstein took SM to exotic pet store > had to be physically restrained from picking up venomous spiders/snakes > she did it bc she knew it was dangerous but she was also curious > absence of normal fearful behaviour
• Feinstein took SM to Wesley State Sanatorium in halloween + SM walked laughing and showing no fear
• Suggests damage to amygdala removes ability to express fear

Question 17

Amygdala: cognitive memories and emotional events

Answer 17

• 1995 earthquake in Japan > ppts were alzheimer ppts + characterised by point of degeneration in patients > followed up to ask detail of their memory regarding the earthquake > more damage to amygdala meant less they remembered.
• Amygdala is important for cognitive memories + emotional events

Question 18

Amygdala as a source of emotional memory

Answer 18

• Amygdala could be relevant to emotions other than fear > what the amygdala does in relation to emotion provides basis for emotional memory
• Amygdala is relevant to rodent fear conditioning (Ploski et Al, 2008)
• Synaptic plasticity is present in amygdala after conditioning
• Brain activity in amygdala increased after fear conditioning + other emotional situations
• Increased blood flow is reflective of increased brain activity in the amygdala during fear conditioning + testing > amygdala is important for fear conditioning and expression of fear
• Amygdala isnt limited to fear + see activation of amygdala when we see food we like, when cocaine addicts see cocaine related video > amygdala is recruited under emotional situations

Question 19

Upstream & downstream

Answer 19

• Amygdala doesn’t operate alone in mediating fearful responses > it is a key aspect to a wider network upstream and downstream
• Upstream = brain areas above regulate amygdala
• Downstream = brain areas below produce the response

Question 20

Prefrontal cortex & emotion

Answer 20

• Is important as this is the area mainly damaged in Phinease Gage > PFC is relevant to aggressive and violent behaviour > responsible for emotional responses
• Amen et Al (1996) found decreased activity of PFC in young people w/ history of violent behaviour > low activity of PFC may link to being more violent
• Raine et Al (1998) found decreased activity of PFC in murderers + increased activity of amygdala
• Ventral PFC is involved in emotional decision making + is not specific to anger + inhibits other emotional states too > found in animal studies

Question 21

Memory extinction

Answer 21

• When the UCS is removed + only CS is being presented, eventually the CR reduces > this process is not unlearning but learning of a new memory that the CS no longer predicts the outcome
• New memory is inhibitory + suppresses exp of old memory > decreases that mem expression (extinction)
• Can recover original memory > original mem never goes away, it is inhibited by new mem but w/ presentation of extinction you get extinction memory

Question 22

PFC & Extinction

Answer 22

• extinction process occurs in the PFC
• Damage to rat infralimbic cortex impairs extinction > releases expression of original memory from inhibition as there is no intact inhibition process
• Similar to what happens in human situations when damage to vPFC is associated w/ anti-social behaviour

Question 23

PFC & Amygdala

upstream

Answer 23

• Network + connectivity between PFC + amygdala is important for regulating emotion
• PFC sends long axons down synapse on the amygdala > we can image the brain + look at how strong the connection is by seeing how many axons there are > stronger the connection, less likely someone shows anxious traits
• Greater the ability of PFC to regulate amygdala, the better control of fear + anxious responses > less likely to suffer anxiety

Question 24

Periaqueductal grey 
(downstream)

Answer 24

• Involved in selection of defensive emotional responses
• PAG is grey region outside aqueduct
• Multiple regions of PAG: dorsolateral PAG + ventrolateral PAG > have different functions related to fear behaviours
• Dorsolateral PAG > important for an active response like running away
• Ventrolateral PAG > related to freezing behaviour in rats

Question 25

Network of emotional regulation

Answer 25

• Amygdala is the seat of emotional memory + produces freezing by activating the ventrolateral PAG > but amygdala is under inhibitory regulation from PFC
• PFC, amygdala + ventrolateral PAG is involved in emotion but have distinct roles in regulation of emotional response