Pain + Placebo Effect
what are nociceptors?
- sensory pain receptors found on free nerve endings throughout the body that
explain the Gate Control Theory of Pain (ex: why shaking a hand helps after closing a drawer on your finger)
- states that pain occurs via two sets of nerve pathways that influence (i.e., act as gate keepers to control) whether pain signals reach the brain. -Small nerve fibers (involved in pain perception) and large nerve fibers (involved in normal perception) synapse onto projection cells. - From there, signals travel to inhibitory neurons and the brain -When there's no sensory input (large fibers stimulated, no pain being perceived), inhibitory neurons prevent projection neurons from sending signals to the brain (gate closed). -When there is a pain signal (small fibers stimulated), the inhibitory neurons are inactivated and projection neurons send pain signal to the brain (gate open). Shaking a hand stimulates large nerve fibers, closing the gate and reducing the perception of pain.
cognitive behavioral therapy
-beliefs about pain -beliefs about controllability -self-efficacy
endogenous opioid peptides
-chemicals produced in many parts of the body -the body's "natural pain suppression system" -endorphins
treatment of pain: surgical
-cutting or creating lesions in pain fibers
phantom limb pain
-mild to extreme pain following amputation -nerve endings continue to send pain signals to the brain -often also experience tingling, cramping, heat and cold MIRROR THERAPY
treatment of pain: pharmacological control of pain
-morphine -local anesthetics -spinal blocking agents -antidepressants Concerns about addictive potential -may result in inadequate pain management in many chronic pain patients
explain how pain serves as a survival mechanism
-motivates us to protect body parts the brain thinks are damaged -provides feedback about how our body functions -tells us when should make adjustments (postural,etc) -suggests we should seek treatment
contributing factors to placebos
-provider behavior -patient characteristics -communication -social norms
name the 2 types of nerve fibers
A-delta fibers: small myelinated fibers, transmit SHARP PAIN C-fibers: unmyelinated fibers, transmit dull, aching pain
nocebo
a harmless substance with harmful effects
pain
an unpleasant subjective experience that MOTIVATES US TO PROTECT body parts that the brain thinks (rightly or wrongly) are damaged
placebo
any medical procedure that produces an effect in a patient because of its therapeutic intent and not its specific nature, whether chemical or physical
name 3 things that make a placebo more effective
any three of: medical/formal setting, staff demonstrates faith in treatment, brand name drug, belief in improvement, bigger pill, more pills, machine > syringe > capsule > pill, more expensive, "shiny and shit," treatment adherence
explain brain plasticity (HINT: think of the rubber hand illusion)
changes in mental body maps -brain maps rubber hand as part of the body -conscious mind completely aware that rubber hand is not part of the body -real hand turns colder as this process happens
treatment of pain: counter-irritation
inhibiting pain in one part of the body by stimulating or mildly irritating another area
chronic pain
lasts 3 months or longer lasts past normal, expected healing period associated w/emotional distress
what are the 3 types of pain receptors?
mechanical thermal chemical
acute pain
momentary intense noxious sensation triggers help-seeking behavior as nociceptin subsides, actual pain subsides
3 pain receptors: thermal
pain due to temperature exposure (ex: sunburn, frostbite)
Nociceptors
pain receptors found on free nerve endings -activated in response to painful stimuli
other treatments for pain
relaxation acupuncture distraction hypnosis
3 pain receptors: mechanical
respond to excess pressure, physical deformation, incisions (ex: cuts)
3 pain receptors: chemical
respond to irritants, environmental toxins (ex: capsaicin = spices)
treatment of pain: biofeedback
training the patient to bring certain physiological processes under voluntary control