NEW335H1 Lecture Notes - Lecture 8: Threshold Of Pain, Fibromyalgia, Sensory Neuron
Lecture 8 – Meditation and Pain
Define pain. Why is pain adaptive?
a) Pain: a distressing experience that is associated with:
1) Tissue injury following exposure to a noxious stimulus – can be studied
objectively
2) The feeling that an injury has occurred (even if no injury is present)–
difficult to study objectively
b) Adaptive: allowing us to identify + withdraw from dangerous situations and
preserving the tissue (sensory receptor in skin ! afferent pathway !
integrating center ! efferent pathway ! effector organs)
oMaladaptive congenital insensitivity to pain: injuries progress
significantly & become severe before being noticed
Differentiate between acute and chronic pain.
a) Acute pain: following an injury ! expected to overlap with the healing
process; short in duration
b) Chronic pain: persistent pain (>3mo) ! extends beyond the expected period of
healing (in some cases – may occur without injury)
➢Important stats:
o~20-40% of population may suffer from chronic pain at some point
oassociated with reduced quality of life, mood disturbances (anxiety/
depression), impaired sleep, impaired memory and reduced employment
oArthritis, fibromyalgia, lower back pain, and irritable bowl syndrome –
common
o~50% chronic pain patients do not feel their pain is properly controlled
! ex: analgesics like opiates have risks of addiction/overdose
oincreased interest in complementary alternative medicine (meditation)
when suffering from neuropsychiatric symptoms
Pain is said to be a private experience. What is meant by this?
•Pain is a private experience that is inferred via subjective report from the
experiment ! many features that a painful experience might have aka
dimensions
Pain perception has several dimensions which can be measured experimentally
using different tests. What are these dimensions of pain? How are they studied?
1) Threshold: defines the point in a stimulus gradient at which pain is first
experienced ! units depend on stimulus (thermal: ˚C, electrical: mA, auditory
stimuli: dB).
oLow pain threshold = weak stimulus can induce pain
oCan be measured easily
Sensitivity: inverse of pain threshold
2) Intensity: the subjective self-report of the strength of the painful experience
ointensity of pain can be estimated via pain rating scales in lab (use of
numbers and letters to describe pain- visual analogs: face scales, and
colour scales)
ousefulness of scale varies: children- face scales, adults: colour +language
scales
3) Unpleasantness: emotional quality we attach to a painful experience !
subjective
oSlightly unpleasant, very unpleasant, extremely unpleasant, pleasant
oWhat you are feeling about the pain is different than how you may
express that pain
What aspect of pain is typically most sensitive to meditation?
•Meditation tends to have the greatest effect on pain unpleasantness
What factors contribute to how we perceive pain?
•Pain = complex experience, affected by:
Attention and emotion changes pain perception. Explain how.
Attention:
oDistraction may reduce the perceived intensity
of pain; less significant effects on the
unpleasantness of pain
Emotion:
oPositive mood may reduce the perceived
unpleasantness of pain; less significant effects on
the intensity of pain
oInvolves ACC and PFC
Document Summary
Pain is said to be a private experience. What is meant by this: pain is a private experience that is inferred via subjective report from the experiment ! many features that a painful experience might have aka dimensions. Pain perception has several dimensions which can be measured experimentally using different tests. What aspect of pain is typically most sensitive to meditation: meditation tends to have the greatest effect on pain unpleasantness. What factors contribute to how we perceive pain: pain = complex experience, affected by: Attention: odistraction may reduce the perceived intensity of pain; less significant effects on the unpleasantness of pain. Emotion: opositive mood may reduce the perceived unpleasantness of pain; less significant effects on the intensity of pain oinvolves acc and pfc. Somatosensory cortex & parts of the insular cortex: affective stage: attaches emotional valance to the painful experience ! can be affected by emotional state, cognitive elaboration, past experiences; characterized by pain unpleasantness.
