Pain Worksheet Flashcards
Explain the finding of the study investigating the sex differences in pain
- No significant sex differences at low temp
- Females reported higher pain at same high heat as males
A-beta fibers
- Information carried
- myelinated?
- Diameter (Smallest to largest)
- Conduction (Slowest to fastest)
- Touch
- yes
- largest
- fastest
A-delta fibers
- Information carried
- myelinated?
- Diameter (Smallest to largest)
- Conduction (Slowest to fastest)
- Pain
- yes
- moderate
- moderate
C fibers
- Information carried
- myelinated?
- Diameter (Smallest to largest)
- Conduction (Slowest to fastest)
- Pain
- no
- smallest
- slowest
Meissner Corpuscle
- Stimulus response
- Fiber type
- Adaptation Rate
- Activation Threshold
- Touch (dynamic deformation)
- A-beta
- Rapid
- Lower
Pacinian Corpuscle
- Stimulus response
- Fiber type
- Adaptation Rate
- Activation Threshold
- Touch (Vibration)
- A-beta
- Rapid
- Lower
Merkle’s disk
- Stimulus response
- Fiber type
- Adaptation Rate
- Activation Threshold
- Touch (indentation depth)
- A-beta
- moderate
- Lower
Ruffini Corpuscle
- Stimulus response
- Fiber type
- Adaptation Rate
- Activation Threshold
- touch (stretch)
- A-beta
- moderate
- lower
Free Nerve Ending
- Stimulus response
- Fiber type
- Adaptation Rate
- Activation Threshold
- Pain
- A-Delta and C
- Slow
- Higher
What receptors are activated when you burn your hand in boiling water
- Free nerve endings
What receptors are activated when you get kicked in the shin
- Free Nerve endings
- merkle’s Disk
What receptors are activated when giving a vigorous handshake
- Free Nerve Endings
- Meissner Corpuscle
Spinothalamic Tract
- Originates in the nociceptor
- Cells extend from A-delta and C-fibers and synapse in the dorsal horn with the second order neurons
- Second-order neurons ascend to the thalamus on the contralateral side
- Second-order neurons synapse with third-order neurons in the thalamus
- third-order neurons terminate in the somatosensory cortex
Lemniscal Tract
- Originates with mechanoreceptors
- Cells extend to form a-beta fibers that synapse in the medulla oblongata with second order neurons
- Second-order neurons ascend to thalamus on the contralateral side
- Second-order neurons synapse in the thalamus with third-order neurons that terminate in the somatosensory cortex
Gait Control Theory
- Applying though to the sight of injury activates the A-beta neuron
- Which activates the interneuron
- The interneuron inhibits the second-order neuron of the spinothalamic tract closing the gait to pain
What aspect of pain perception does acetaminophen impact?
Emotional
What brain regions are involved in emotional pain
Insula and ACC
What impact did acetaminophen have on the participant’s pain perception in De Wall et al (2010) study
Reduces activation in the insula and ACC, which reduces feelings of hurt caused by social rejection
How can chronic back pain impact the brain?
- Increased activity of insula
- decrease in grey matter density in the prefrontal cortex
What is the impact of increased activity of the insula caused by chronic back pain?
Increased hyperalgesia/ sensitivity to pain
- can relate to increased rates of anxiety and depression in individuals with chronic back pain
What is the impact of decreased grey matter density in the prefrontal cortex?
reduction in cognitive function, specifically executive function related to decision making
What are the similarities between phantom limb pain and allodynia
Both result from maladaptive neuroplasticity
What are the differences between phantom limb pain and allodynia
- One is due to maladaptive neuroplasticity in the spine and the other is in the somatosensory cortex
- Damage to nerve vs loss of limb
- Does not respond to mirror therapy vs does
How does intention affect pain when someone hurts you?
Malicious intent causes an increase in pain
How does attention affect pain perception
- Not attending to pain decreases how much it hurts
-Periaqueductal Grey (PAG) becomes more activated
-Prefrontal cortex inhibition of the PAG when attending to pain
How does more intense pain affect perception of moderate level pain?
- More intense pain inhibits moderate pain
- Periaqueductal gray (PAG) released endogenous opioids which bind to opioid receptors to inhibit pain and raises threshold for pain (analgesic effect)
Pain in neonates
- Neonates feel pain
- historically, insufficient scientific understanding of the brain meant that neonates were not offered pain relief, even for major surgeries
Characteristics of Pain
- unpleasant at both sensory and emotional levels
- potentially but not necessarily associated with tissue damage
- Subjective
Non-verbal response to pain
- Facial expressions
- Crying characteristics
- Cortisol levels
- Neural Activity
How do expectations influence pain?
- Positive and negative expectations elicit powerful placebo or nocebo effects
- Anxiety about pain increases the pain
Def: Empathy
Feeling another’s pain
Compared to pain administered to self, what does empathy cause
- No activity of the somatosensory cortex
- Similar activation of the insula and ACC
- Activation of the insula depends on the extent to which one feels empathetic
Distinctions between social and physical pain
- Social pain appears to hurt more than physical pain when relived
- Context matters
How long must pain persist to be considered chronic pain?
longer than 3 months
What are the three types of chronic pain
- Nociceptive - Tissue damage
- Neuropathic - Nerve damage
- Nociplastic - Sensitized nervous system
What causes chronic pain?
- Dysfunctional neuronal signaling in the periphery, dorsal horn and cortex
- Resulting in neural degeneration that impairs pain perception, mood and decision making
How can chronic pain be treated
-Hyperalgesia may benefit from opioids but there are risks of addiction
- Allodynia is resistant to opioids
-talk therapy and physiotherapy may be the best approaches to rewire the nervous system for nociplastic pain
Explain the Rubber Hand Illusion
- Visual input tricks the brain into believing the rubber hand is your real hand
-Causes temporary representation of the rubber hand in somatosensory cortex
Virtual reality effect on neck pain
- Visual information tricks the brain into thinking the head has rotated more or less than it has
What causes phantom limb pain?
-Neighboring body parts takeover the S1 area that used to represent the amputated limb
- When that region is activated, it can cause pain in the former location of the amputated limb
Function of mirror therapy
Helps to suppress S1 activity and phantom pain
