Chronic Pain

Question 0

Nociceptors in Medial Pain Pathway

Answer 0

C-fibers

Question 1

Nocicepters in Lateral Pain Pathway

Answer 1

A-delta

Question 2

Cortical areas activated w/ acute pain

Answer 2

S2 and Insula-acitvated first

S1
Anterior Cingulate
Motor/Pre-motor areas

Question 3

Anterior cingulate pain processiong

Answer 3

Anterior- Memory/emotional aspects of pain

Posterior- Sensory aspects of pain

Question 4

Default Mode Network

Answer 4

Consists of medial prefrontal cortex, posterior cingulate gyrus, and precuneus

-Involved w/ daydreaming; not focused on external environment

Question 5

Chronic Pain and the DMN

Answer 5

Both insula and DMN activated simultaneously; shift in favor of pain experience when gray matter starts dying

Question 6

Traumatic neuroma

Answer 6

Trauma to a periperhal nerve causing proliferation of Schwanna cells and axons

Produces increased Na+ channels and TRP channels leading to ectopic discharges and thermal hyperalgesia

Question 7

Wind-up pain (Segmental Level)

Answer 7

Repeated firing of C-fibers due to excess release of Glu and SP @ nociceptors

-Metabotropically closes post-synaptic K+channels and opens NMDA channels allowing Ca+ influx
=>depolarized state causing secondary axons to fire easily
(long-term potentiation)

Question 8

Cl- mediated allodynia (Segmental Level)

Answer 8

Neuronal inflammation causes recruitment of microglia which release BDNF

-BDNF alters Cl- causing Ecl to be negative to AP threshold leading to decreased activation of GABAa and glycine receptors

=>DECREASED INHIBITION OF A-DELTA FIBERS

Question 9

Areas activated in Chronic Back Pain

Answer 9

Anterior Cingulate & PFC

Question 10

Areas activated in Pre-herpetic neuralgia

Answer 10

Anterior Cingulate & Insula

Question 11

Medial Pain Pathway

Answer 11

Input from C-fibers relays thru the reticular formation

-Eventually reaches thalamus & amygdala