Neuroscience of Pain and Reward

Question 1

What is psychological hedonism?

Answer 1

perspective arguing that peopl are motivated to act in ways to inc and maximize pleasure and minimize and avoid pain

Question 2

Reward vs. pleasure

Answer 2

Reward: something an animal will work to achieve
Pleasure: the subjective hedonic value of rewards

Question 3

Primary vs secondary reward

Answer 3

Primary: naturally rewarding stimuli and biologically essential
Secondary: learned rewards that gain importance through repeated associations

Question 4

Punishment vs pain

Answer 4

Punishment: something an animal will work to avoid
Pain: the subjective hedonic and motivational response to a punishing stimuli

Question 5

Primary vs secondary punishment

Answer 5

Primary: painful stimulus itself, naturally aversive
Secondary: leaned punishment through experience

Question 6

What is subjective utility?

Answer 6

the idea that rewards don’t always produce pleasure and punishments don’t always cause pain, the personal value and satisfaction an individual assigns to an outcome based on their preferences and circumstances

Question 7

What is alliesthesia?

Answer 7

The subjective hedonic value of a stimulus is tied to extent to which a stimulus contributes or disrupts homeostasis

Question 8

What is the difference between pain and nociception?

Answer 8

pain is an unpleasant sensory or emotional experience and nociception is a neural processing of tissue damage (detection and transmission of info)

Can have pain without nociception (ie. phantom limb) and nociception without pain (withdrawal reflex)

Question 9

What are the two components of pain?

Answer 9

1) sensory-discriminative component
- provides info about intensity, quality and location
- processed in primary and secondary somatosensory cortices and posterior insula
2) affective-motivational component
- relates to the emotional experience of pain and drives motivation to escape the pain
- processed in the dorsal anteior cingulate cortex (dACC) and anterior insula

Question 10

What is some evidence of shared sensitivity to physical and social pain?

Answer 10

• greater baseline sensitivity to physical pain predicts greater sensitivity to social exclusion
  -a genetic variant related to greater physical pain sensitivity is related to greater trait rejection sensitivity, greater self-reported subjective and neural reactivity to cyberball, and more sensitivity to hurtful partner behaviour

Question 11

What is some evidence of the social pain hypothesis?

Answer 11

• Cyberball study: neuroimaging showed INC activation in dACC and anterior insula where the magnitude of neural activation correlates with both self-reported feelings of social exclusion and observer-rated social distress
  -Photos of rejecting ex-partner, also shows inc activation of dACC and AI

Question 11

What is the evidence that factors that increase/decrease one type of pain have the parallel effect on the other type of pain?

Answer 11

factors that decrease social pain also dec physical pain
ex) social support decreases physical pain (during labour) This is reflected in decreased signalling in dACC and AI in response to pain tas l
Factors that inc social pain are more complex
ex) cyberball exlcusion has been shown to lead to pain hypersensitivity, most excluded feel the most pain, also premeditated pain hurts more than accidental pain
But social exclusion has also been linked to hypoalgesia (reduction in pain) , emotional numbing –> less pain

factors that dec physical pain have parallel effects on social pain ex) Tylenol takers report lower levels of hurt feelings than placebo placebos

factors that increase physical pain have parallel effects on social pain ex) inflammatory challenge INC interpersonal sensitivity

Question 12

What are behavioural consequences of social pain?

Answer 12

Neuropsychological evidence: in animals, dACC lesions lead to decreases in separation distress and deficits in social behaviour (maternal behaviour, social interest, proximity seeking)

Experimental evidence: social pain drives affiliative behaviour
- inc desire to work with others vs alone
-more effort on group task
- more likely to sign up for friend match-making
-more social monitoring
provide more positive evauations of a new partner

Question 13

What is the caveat of behavioural responses to social pain?

Answer 13

we are likely to engage in affiliative behaviour only to the extent to which we see the target as a viable source of social connection
This means people whoa re fearful of negative evaluation are less likely to reach out post rejection

Sometimes social pain leads to aggressive behaviour

Question 14

What is the difference between wanting and liking?

Answer 14

Liking is described as the subjective feeling of pleasure we experience when we receive a reward

Wanting is the motivation to pursue something

Question 15

how do we measure liking and wanting?

Answer 15

liking: typically measured by asking, and sometimes by physical indicators (facial expression)

wanting: typically measured by amount of effort an individual is willing to exert to obtain the reward

Question 16

How is beauty a reward?

Answer 16

Beauty is a primary reward because it signals health, fertility, genetic fitness
The brain processes facial attractiveness similarly to how it processes other rewarding stimuli

Question 17

How does dopamine play in processing reward?

Answer 17

“the pleasure molecule”
Now understood as playing a large role in WANTING rather than liking
The Dopamine-based reward circuit involves the VTA, NA, PFC, and OFC

Question 18

VTA

Answer 18

Ventral tegemental area
where dopamine is made

Question 19

NA

Answer 19

Nucleus Accumbens
the brain’s pleasure centre

Question 20

PFC

Answer 20

Prefrontal Cortex
Involved in decision-making and self-regulation

Question 21

OFC

Answer 21

Orbitofrontal cortex
Key to evaluating rewarding stimuli

Question 22

How does the dopamine reward circuit work?

Answer 22

Dopamine is released when a reward is evaluated and a positive prediction error happens when an outcome is better than expected

Dopamine release is greatest when a reward is unexpected, and or under-predicted and is even greater during anticipation

Question 23

What role do endogenous opioids play in reward processing?

Answer 23

Play a large role in LIKING (pleasure) - the opioid system is closely related to the dopamine system -Opioids mediate pleasure stemming from a variety of stimuli (ex. tasty foods, exercise, sex, drugs, alcohol, social play)

Question 24

How can we examine the role of opioids?

Answer 24

By adminstering opioid antagonists (naltrexone or naloxone) to block the signals, we can use neuroimaging to look at opioid release and correlate extent of opioid release with subjective feelings

Question 25

What is the Motivation-decision model of pain?

Answer 25

Subjective interpretation of a sensory event can be understood as a manifestation of the unconscious decision process - main idea is that decisions are based on what is most critical for survival in the moment--> if something more important than pain is happening the brain can reduce pain signals Involves 3 factors: - internal state -sensory input -Threats and Rewards

Question 26

When is the brain most -likely to reduce pain signals?

Answer 26

can be for fight or flight Also a variety of rewarding stimuli have been shown to reduce pain in humans and non-human animals (sweet foods, pleasurable odours, sexual behaviour, pleasant music) EXPECTATION of reward also reduces pain ex) placebo analgesia ex) hungry rats who learn a shock means food show attenuation of pain response

Question 27

What biological mechanisms affect analgesia in the motivation-decision model?

Answer 27

Endogenous opioids produce both stress and pleasure induced analgesia Hungry rat who attenuates pain response to shock that means food--> this can be undone with opioid antagonists. Placebo analgesia is a classic example - the magnitude of placebo analgesia correlates with opioid release in brain

Question 28

What is placebo analgesia?

Answer 28

a (reduction in pain that occurs after a person is given a placebo, an inert substance which has no effect but which the person believeswill attenuate their pain

Question 29

What is Anhedonia?

Answer 29

the inability to enjoy everyday pleasures - often caused by inhibition of reward by pain, where pain decreases engagement in rewarding activities ex) high co-morbidity between chronic pain and depression

Question 30

At the neuroanatomical level, what are the points of overlap between pain and pleasure processing discussed in class

Answer 30

Opioids and dopamine are both important for regulating pain and pleasure. Neural regions like... ACC: represents the size and probability of rewards as well as effort required Insula: encodes taste and food craving, linked to felt satisfaction, and interoceptive signals Amygdala: involved in both pain/threat processing as well as reward

Question 31

Why do we sometimes seek out pain?

Answer 31

The relief of pain is itself a pleasurable experience. Sometimes negative stimuli can be experienced as pleasant when in the context of more negative stimuli Experience of moderate pain can be reported as pleasant when compared to alterntative extreme pain

Question 32

What is relative relief? What is evidence of this?

Answer 32

the experience of pain being pleasant when compared to other, more intense pain LAB STUDY: Ps subjected to painful task (like skin irritant) when painful sensation stops, a sense of relief and positive affect results the more intense the pain the more intense the relief

Question 33

What is the opponent process model?

Answer 33

Emotional reactions are regulated by the brain to maintain hedonic balance. Strong emotional reactions (both pleasure and pain)are countered by an opposite reaction Involves state A and B: - State A is an emotionally powerful stimulus, develops quickly and ceases when stimulus is removed. The brain is counteracting the fear - State B is the ful lforce of relief and excitement is felt, it develops slowly after state A, state B then slowly fades until emotions return to baseline

Question 34

According to opponent process model? what happens with repeated stimuli?

Answer 34

state B becomes more intense over time Because steady State A = A –B, repeated presentations of stimulus that triggered State A will lead to a reduction in hedonic intensity of State

Question 35

What is the Peak-end rule?

Answer 35

The most intense positive or negative moments or the final moments (peaks and ends) of experiences are most heavily weighted in our recollections of experiences