Week 1 - Lecture 1 - Pain pathways and modulation Flashcards

Question

Is the pain perception the same in everyone? Yes or no and explain why.

Answer 1

* Objective and subjective aspects of injury and pain are DIFFERENT! * Despite similar injury, people can differ in how much pain they feel * Depending on the context, pain may not be felt despite injury * Suggests that a physiological mechanism controls the transmission of nociceptive signals to the brain or modifies the interpretation of pain

Answer 2

MODULATION Flinch away from it Tense up Rubbing it Why do we do that? It’s maybe a distraction, your changing some sensory input into your body (override that painful experience)

Answer 3

Gate control theory Blocking ascending pathway Descending Pain Control Expands on Gate Control theory with input from higher brain centers Endogenous opioids Nociceptors to stimulate the release of endorphins, bind to blobk pathway

Answer 4

The concept of the gate control theory is that non-painful input closes the gates to painful input Ascending Aβ fibers block pain impulses at the spinal cord level carried along Aδ and C fibers Results in prevention of the pain sensation from traveling to the central nervous system \*\*\* Inhibitory neuron = Little yellow i = is always on and is making sure that the non-painful input closes the gates to painful input A-beta neuron = L in green Large fiber travels faster than a small fiber = which allows to essentially

Answer 5

(L) Large diameter, myelinated (fast– can beat pain) - Stimulates projection cell (P) - Stimulates inhibitory neuron (i) (S) Small diameter, myelinated/unmyelinated (pain) - Stimulates projection cell (P) - Inhibits Inhibitory neuron (i) • Occurs whether or not signal reaches brain (top) • E.g., rub thumb after hitting it with a hammer

Answer 6

- Activity from descending fibers (e.g., PAG) project to the dorsal horn and could also modulate this gate (inhibit/facilitate) - Nociceptive information reaches a threshold that exceeds the inhibition elicited - It “opens the gate” and activates pathways that lead to the experience of pain and its related behaviors. \*\*\*Trying to block the signal in getting to that second order neuron, in addition to the gate control theory Inhibition of the signal but the signal continues and is too strong (and we can’t override it), it can override the descending pathways and that reenforces the urge to, for example, move your hand Abnormality in this system can lead to chronic pain : the pain is not inhibited. Lots of different ways that can happen

Answer 7

• The brain releases endogenous opioids in response to pain perception • Internally produced molecules with opioid-like action to regulate transmission of nociceptive signals • Similar brain regions that modulate the signal from nociceptive afferents • Distribution varies by endogenous opioid family

Answer 8

Three classes: Enkephalins Endorphins Dynorphins Produced by the same brain regions and that there are these 3 classes that exist = is what you need to know Don’t have to know the details, how they function or where they come from

Answer 9

• Inhibitory effect on nociception • Slower but has a longer lasting effect • We naturally express the receptors for these molecules thus allowing the chemical to bind for a long period of time • Relies on circulation of chemical versus action potential along neurons • E.g., prescribe ROM (within a pain free range) \*\*\*Bad circulation = these will not function as well, because they won’t get to the root of the problem(increasing circulation = better) Prescribing simple ROM (range of motion)= will increase blood flow and also increase the release of those natural opioids

Answer 10

Melzack's: pain experience Neuromatrix theory: Motivational Affective = like the unpleasant of it Cognitive Evaluative = has to do more with the cognitive state, perhaps different cultural views, is the pain perceived as good or bad Sensory Discriminative = physiological characteristics of the pain