lecture 9 - pain and social pain

Question 1

pain

Answer 1

An unpleasant sensory and emotional experience associated with actual or potential tissue damage

has intensity, implying that it can be measured
- Has character (ex. Sharp, Dull, Burning, Aching)
- Pain is subjective

Question 2

list what pain can be modulated by

Answer 2

Ascending and Descending Pathways
o Salience Network (what to pay attention to)
o Modulation Network (top-down control, neurochemical pain killers)
o Physically manipulations (ex. medication, massage, etc)

Question 3

what is acute pain

Answer 3

<6 months

immediate response from injury or disease (with limited duration)

responsive to pharmacological treatments

Question 4

what is chronic pain

Answer 4

> 6 months
not responsive to pharmacological treatments

Question 5

touch receptors come from …

Answer 5

hair (vibrational)

Question 6

stretch receptors respond to…

Answer 6

pulling and condensing of muscles

Question 7

wide, ridged receptors respond to…

Answer 7

vibration and pressure (texture)

Question 8

list 3 types of sensory receptors

Answer 8

touch receptors
stretch receptors
wide ridged receptors

Question 9

free nerve endings

Answer 9

pain receptors that are closest to the surface of the skin and don’t have caps that other nerve endings have

Question 10

nociceptors

Answer 10

sensory neurons that respond to damaging / potentially damaging stimuli (specifically pain receptors)

transmit pain info to ipsilateral side of spinal cord (the side stimulated is the side that is received in spinal cord)

Question 11

what are free nerve endings specific for

Answer 11

pain and temperature

Question 12

what is the purpose of myelin in A-delta fibres

Answer 12

AP can be propageted down the axon faster thanks to the myelin

Question 13

Why are C fibres different from A fibres?

Answer 13

C fibres have no myelin so the AP moves slower

Question 14

specificity theory

Answer 14

causal relationship between pain stimulus and receptors

Question 15

stimulus intensity is also called

Answer 15

pain intensity

Question 16

issues with specificity theory

Answer 16

• there is no specific cortical location for pain
• pain fibres can be used for other purposes (like pressure and temperature)
• it doesn’t explain the diffs in peoples reports of pain

Question 17

describe the spinothalamic tract process of pain

Answer 17

sensory neurons conduct and transmit painful stimuli from peripheral nervous system to CNS (the spinal cord)

nociceptors transmit pain information to ipsilateral (same) side of the spinal cord

pain signal crosses to the contralateral (opposite) side of spinal cord

transmission ascends spinal cord through brainstem VPL nucleus of thalamus

signal transmitted from thalamus to somatosensory areas of cerebral cortex

pain received on the right side of the body will be processed in the left hemisphere of the brain and vice versa

Question 18

pattern theory

Answer 18

nociceptors generate repeated or very large signal in the spinal cord which gets passed to the brain to perceive the pain

the signal is only transmitted if it passes the threshold

Question 19

flaws of pattern theory

Answer 19

doesnt explain deferred pain (like feeling period cramps in legs or back instead of uterus)

doesn’t explain pain without injury (or injury without pain) bc there is no stimulus to drive the APs

Question 20

gate control theory

Answer 20

c fibre activates the inhibitory interneuron since no pain is observed. the signal therefore is not sent to the brain

c fibre inhibits the inhibitory neuron if pain is observed. signal is then sent to the brain.

pain can reactivate the inhibitory interneuron, partially allowing the inhibitory interneuron to do its job (block the pain signal ascension). the signal to the brain conveys slight pain.
- example of this is rubbing your knee after u bang it to make it feel better

Question 21

pain modulators

Answer 21

can be physical or psychosocial

physical
- block pain from being transmitted up to brain (ex; medication)

psychosocial
- how much attention u have on the pain, how u interpret the pain, and diff coping strategies used

Question 22

operant conditioning and pain

Answer 22

pain is a unpleasant sensation and leads to behaviour

Question 23

classical conditioning and pain

Answer 23

pain is a particular situation or environment that is associated w pain/ anxiety/ depression

Question 24

fear avoidance model

Answer 24

avoidance is associated w catastrophizing patients. if pain is interpreted as threatening, this fear evolves

avoidance behaviour leads to mainteneance or exacerbation of fear, hypervigilance to internal and external illness information, and muscular reactivity

confrontation leads to reduction of fear over time

Question 25

list the cortical areas involved in pain and what they do

Answer 25

anterior cingulate cortex: pain unpleasantness

insular cortex: pain unpleasantness

S1(primary somatosensory cortex): pain sensation, location, modality

S2(secondary somatosensory): same as s1

prefrontal cortex: pain regulation

limbic areas: pairs pain with other aspects like emotion, fear, memory, etc

Question 26

subjective pain experience study Coghill et al

Answer 26

purpose: explore conscious sensory experience from 3rd person observation and identify neural correlates of someones pain experience in relation to others receiving the same stimulus

method:
rated temp stimuli applied to their forearm and split into groups based on pain sensitivity

low= insensitive to pain, high = sensitive

fMRI was done while having paritipents forearm stimulated with heat

results:
- cortical regions related to sensation, attention and affect were most associated with pain sensitive ppl vs pain insensitive (prefrontal cortex, S1)

• all sensitive ppl had ACC activation, no activation for all of the insensitive ppl
• activation in thalamus was same for ALL subjects, showing everyone’s pain signal did make it to the brain via spinothalamic tract

pain reports resulted in real brain activations!

Question 27

phantom limb

Answer 27

sensation that an amputated or missing limb is still attached

can range from twitches to full range motion or control

can be painful

Question 28

possible mechanism for phantom limb (there are 2 listed here)

Answer 28

mirror therapy

a person who can see their other limb moving in a mirror “in response to” the movement their nerves in the amputated limb want to do, this can bring relief to the phantom limb phenomenon.
- hyper excitability in peripheral nerves or CNS

mirror neurons
- found in animal studies which fire when animals perform or observe an action
- therefore, by receiving tangential visual input of perception and tactile sensations, the brain can limit the amount of pain u are experiencing from it

Question 29

congenital universal insensitivity to pain (CUIP)

Answer 29

inability to perceive physical pain but can tell difference from diff amounts of touch, temp, etc

present from birth

can lead to injury or death as u cant tell if u are injured

Question 30

what may cause CUIP?

Answer 30

SCN9 gene; responsible for instructions to make the alpha subunit part of the sodium channel (Na V1.7)

absence of functioning NaV1.7 channels impairs transmission of pain signals, causing those affected to be insensitive to pain

Question 31

social pain + social exclusion: Macdonalds and Leary

Answer 31

Being socially excluded feels awful
- But more than that, it actually hurts
- English speakers tend to use physical injury-related terms to describe social injury

Question 32

Jaak Panksepp - morphine

Answer 32

morphine calms distress of social isolation in animals

injections of morphine quieted the distress vocalizations of maternally isolate guinea pigs (fewer vocalizations of guinea pigs injected with morphine)
- Panksepp conjectured that the social distress system overlaps with the more ancient physical pain system
- The endogenous brain opioid system may be one of the neurochemical regulators of the distress associated with social separation, as well as the pleasure associated w/ social connection (Eisenberger, 2012)

Question 33

does swearing cure pain? Stephens and Roberston

Answer 33

IVs: Type of swear words
o Conventional (Fuck)
o “New” (Fouch, Twizpipe, etc)
o Neutral (any word)
- DVs:
o Ratings of emotion, humour, distraction
o cold pressure pain threshold
o cold pressor pain tolerance
o pain perception score
o change from resting heart rate
- They were able to keep their hand in the cold water longer when they used the conventional swear words
- It’s the context of the emotion that influences pain (not necessarily the emotion itself)?

Question 34

Eisenberger et al - cyberball task

Answer 34

Participants played a game of Cyberball under 3 conditions, while imaging brain activity with fMRI:
1. Excluded due to technical difficulties
2. Included
3. Excluded due to rejection by other players (who are actually not playing with you, they are part of the computer simulation)
- Found greater activity in the dACC and 2 regions of the right ventrolateral prefrontal cortex during exclusion than during inclusion
o These same brain regions are activated in response to physical pain
- Does depend on personality traits!
o More neurotic people are more sensitive to physical pain and more sensitive to rejection
o More extroverted people are less sensitive to physical pain and less sensitive to rejection

Question 35

social pain implications - Dewall et al

Answer 35

experiment 1
Randomly assigned participants to receive:
* Daily dose of Tylenol (1000mg) OR…
* Placebo over period of 21 days
Each evening, participants recorded questions regarding degree to which they felt emotionally hurt during the day
o Results:
Placebo group: no change in hurt feelings over 21 day period
Tylenol group: significant decline in hurt feelings over the 21 day period
o People were physically experiencing less pain also experienced less social pain

experiment 2
Randomly assigned to take:
* 1000mg Tylenol Morning, 1000mg Tylenol at bed OR…
* Placebo of same dose (n=25)
*
3 weeks later –fMRI lab experiment, ball tossing game (social exclusion task)
o Results:
Compared to placebo group, participants who took acetaminophen showed less activity in dACC and anterior insula in response to cyberball exclusion
o By manipulating the ability to feel pain in the brain, you can also manipulate the ability of the brain to feel emotional pain
BUT dangerous path to addiction…

Question 36

prevention of psychological and pain disorders with morphine

Answer 36

ppl given morphine immediately following a traumatic event are less likely to develop PTSD

Question 37

how may opiates interfere with memory consolidation?

Answer 37

through a beta-adrenergic mechanism

also have to consider addiction