pain

Question 1

pain

Answer 1

• aversive sensory experience
• caused by actual or potential injury
• elicits protective motor & vegetative (freezing) reactions
• results in learned avoidance
• may modify species-specific behaviors
• biological importance
  
  • ↓ performance of dangerous behaviors
  • ↑ survival
  • ↑ fitness
  • if you’re sick (neuropathic pain), you know to rest & conserve energy

Question 2

noxious stimuli

Answer 2

something perceived in envir that can damage tissue

• mechanical = pressure/cutting
• thermal = burns/freezing
• chemical = acid burns
• conditioning examples:
  
  • electric prod to get them to stop standing still = + punishment
  • electric prod while they walk to get them to keep walking = + reinforcement
  • electric prod = giving shock

Question 3

types of pain

Answer 3

nociceptive pain from direct activation of pain nerve fibers

• nociceptors detect noxious stimuli
• causes avoidance behavior

neuropathic pain generated or sustained by NS

• chronic, inflammation, autoimmune
• sickness (cold, flu, etc.)

Question 4

assessment of pain

Answer 4

objective

• physiological
• behavioral
• more accurate & common

subjective

• self-reported (pain scale)
• descriptive

Question 5

physiological assessment of pain

Answer 5

• dilation of pupils &/or widening of eyes ➔ bringing in as much info as survival strategy
  
  • negative affective state = everything is a threat (cognitive bias)
• changes in BP/HR
• ↑ RR
• piloerection = puff out feathers ➔ makes them look larger & thermoregulation (ex: mice)
• changes in skin & body temp
• ↑ muscle tone
• sweating (ex: horse with severe colic)
• ↑ defecation & urination
• ex: newborn piglet processing performed w/out analgesic/anesthesia
  
  • physiological assessment of pain: meloxicam through sow’s milk
  • physiological indicator of pain = ↓ facial temp: blood goes to site of pain

Question 6

behavioral assessment of pain

Answer 6

choice/preference to avoid pain

• avoiding painful stimulus
  
  • ex: free-swimming goldfish chose to stay in area of pond with no shocks (not associated with pain)
• self-medication w/ analgesics
  
  • ex: lame broiler chickens preferentially eat feed with pain medication (NSAID)

pain-specific behaviors

• posture ➔ ex: dogs’ hunched over/arched back for abdominal pain
• facial expression
  
  • ex: mouse grimace scale:
    
    • tightly closed eyelid or squeezed/scrunched eyes
    • skin around nose is rounded
    • ears are pulled back & apart
  • ex: grimace scale in horses:
    
    • ears backwards
    • tightening & tension above & around eyes
    • bulging/strained masseter muscles, mouth, & chin
    • strained nostrils
• vocalization
• gait
• site specific behavior
  
  • ex: disbudding: preventing horn grown in calves by cauterizing tissue around the horn buds without pain relief
    
    • calves show high frequency of head-shaking (site of pain) after procedure
    • calves given NSAID shake their head less after disbudding
  • ex: castrated ram lambs tuck in hind limbs but non-castrated ram labs will extend hind limbs while resting
  • ex: atlantic cod that were induced with pain shook heads & hid in tank more than fish not given painful procedure ➔ site-specific & activity budget changing during pain

change in activity budget: reduced activity, feeding, drinking, playing

Question 7

Why display behavioral indicators of pain?
What is the evolutionary advantage to advertising pain experience?

Answer 7

true communication between family ➔ family sees your adverse response to food or injury from an action ➔ they avoid those things too

Question 8

What is the evolutionary advantage to hiding pain experience?

Answer 8

• showing pain makes you look weak ➔ easier prey for predators
• evolutionary basis to hiding pain ➔ deters predators
• ex: laying hens with arthritis will walk on injured leg when placed in novel arena alone