B2 Tracts

Question 1

What is the one lateral sensory discriminative pathway?

Answer 1

Neospinothalamic pathway

Question 2

What are the 3 functions of the neospinothalamic pathway (lateral sensory discriminative)

Answer 2

1. Interpret pain
2. Organised somatotopically to permit localisation
3. Small receptive site = better localisation

Question 3

What are the 6 steps of the neospinothalamic pathway (lateral sensory discriminative)?

Answer 3

1. Nociceptors → 1st → 2nd → Brainstem
2. VPL thalamus - crude pain
3. Internal capsule posterior limb
4. Corona radiata
5. Primary somatosensory cortex
6. Secondary somatosensory cortex - intrepret pain

Question 4

What are the 4 medial affective motivational pathways?

Answer 4

1. Paleospinothalamic pathway
2. Spinohypothalamic pathway
3. Spinomesencephalic pathway
4. Spinoreticular pathway

Question 5

What is the function of the paleospinothalamic pathway?

Answer 5

Dorsomedial & intralaminar nuclei project to cortical association areas & limbic ⇒ emotion & memory

Question 6

What are the steps of the paleospinothalamic pathway?

Answer 6

1. Nociceptors → 1st → 2nd → Brainstem
2. Thalamus: Dorsomedial & intralaminar nuclei
3. …
4. Amygdala, cingulate cortex, insula, hypothalamus

Question 7

What is the function of the spinohypothalamic pathway?

Answer 7

Hypothalamus controls autonomic response to pain: e.g. HR, respiratory rate, sweat

Question 8

What are the steps of the spinohypothalamic pathway?

Answer 8

1. Nociceptors → 1st → 2nd → Brainstem
2. …
3. Hypothalamus

Question 9

What is the function of the Spinomesencephalic pathway? What are the 3 functions of the peraquaductal grey?

Answer 9

Periaqueductal gray:

• Output to dorsal horn ⇒ modulation of pain
• Superior colliculus: ⇒ reflex eye movements toward source of pain
• Mesencephalic reticular formation – amygdala ⇒ emotional aspects of pain

Question 10

What are the steps of the spinomesencephalic pathway?

Answer 10

1. Nociceptors → 1st → 2nd → Brainstem
2. …
3. Periaqueductal gray
4. Superior colliculus: output to tectospinal tract - look at where pain is

Question 11

What is the function of the spinoreticular pathway? What are the 3 functions of the reticular formation in brainstem?

Answer 11

Reticular formation in brainstem:

• Output to dorsal horn ⇒ modulation of pain
• Output to ventral horn ⇒ motor response to pain
• Output to cortex, basal nuclei, cerebellum, thalamus, ⇒ arousal, attention to stimuli

Question 12

What are the steps of the spinoreticular pathway?

Answer 12

1. Nociceptors → 1st → 2nd → Brainstem
2. …
3. Reticular formation throughout brainstem