Medial Pain system

Question 1

What are the five main functions of the medial pain system?

Answer 1

1. limbic and autonomic activation
2. learning and anticipatin
3. nocifensive behavior
4. empathy
5. inhibition

Question 2

What are the three main ascending spinal pain systems?

Answer 2

1. direct anterior lateral pathway
2. indirect anterior lateral pathway
3. posterior medial pathway

Question 3

What are the 3 types of indirect anterior lateral pathways?

Answer 3

1. paleospinothalamic
2. . spinoreticular
3. spinomesencephalic

Question 4

Describe the paleospinothalamic pathway

Answer 4

1. axons ascend bilaterally - ventrolateral spinal cords
2. synapse in RF, MITTN
3. project to anterior cingulate and insular cortex

Question 5

Describe the spinoreticular pathway

Answer 5

1. axons ascend bilaterally
2. terminate at two levels of the RF
   -caudal–>IML cell column
   regulates sympathetic nervous system
   -rostral and locus coerulus –> PVN

Question 6

Describe the spinomesencephalic pathway

Answer 6

1. axons from dorsal horn and intermediate gray
2. ascend to midbrain and PAG
3. PAG neurons regulate ANS
   - transmit ascending info to amygdala via parabrachial nucleus
   - descending projections inhibit pain sensation

Question 7

What do the posterior medial pathways transmit?

Answer 7

visceral nociceptive information

-changes in temp,pain, irritation, chemical changes, stretch

Question 8

How does the distribution of receptors in the posterior medial pathway relate to the perceived pain?

Answer 8

pain is poorly localized since receptors are widely scattered

Question 9

Describe the steps of the posterior medial pathway?

Answer 9

1. initial afferents run with vagus and sympathetic nerves
2. projections from lamina x neurons synapse in gracile nucleus
3. to VPL –> insula
   to central lateral thalamus –> ACC

Question 10

What does the mesencephalic and rostral pontine formation of the reticular formation regulate?

Answer 10

forebrain activity

Question 11

what does the caudal pontine and medullary reticular formation regulate?

Answer 11

premotor coordination of lower somatic and visceral motor neuronal pools

Question 12

What is the function of the locus coerulus?

Answer 12

integrates diverse signals which alert and orient the brain to significant events
-primes neuroendocrine and limbic systems for actions or reactions

Question 13

What is the function of the MITTN?

Answer 13

engages multiple cortical areas involved in pain perception and the reactions to it

Question 14

PAG and RF regulate the ans via projections to what three nuclei?

Answer 14

NTS, DMX, IML

Question 15

The anterolateral system sends projections to the ventral posterior nucleus –> somatosensory cortex which do what?

Answer 15

sensory, discriminative aspects of pain

-location, intensity, quality

Question 16

What is the function of the neurons sent by the anterolateral system to the:
Amygdala
Hypothalamus
PAG
Superior Colliculus
RF

Answer 16

Affective - motivational

-conveys information about the unpleasant feeling, fear and anxiety and autonomic activation that accompany pain

Question 17

The anterolateral system sends projections to the midline thalamic nuclei, which continue to the ACC and insular cortex. What are these fibers involved in?

Answer 17

also affective - motivational

Question 18

The rostral ACC is involved with what type of stimulation? caudal ACC ?

Answer 18

rostral - visceral stimulation

caudal - cutaneous