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