Intro to Somatosensory Pathways - Michaels

Question 1

What is Brown Sequard Syndrome?

Answer 1

AKA hemiplegia

Loss of sensation and motor function due to lateral hemisection of the spinal cord!

Question 2

Convergence:

Answer 2

Receptive fields of 2nd order neurons often overlap producing a population response. Therefore stimulation of a small area of skin (point of convergence) could activate multiple 2nd order neurons

Question 3

Where does sensory info involved in the spinothalamic tract cross the midline?

Answer 3

Anterior white commisure

Question 4

Cordotomy: surgical cutting of ventrolateral funiculus

Result?

Answer 4

Cordotomy may be performed bilaterally in terminally ill patients (produces bilateral analgesia and athermia several dermatomes below lesion)

Question 5

• Syringomyelia

what is it?

Answer 5

A “hole” develops (cyst) in the center of the cord and expands out and rostral/caudally (up to several inches)

Can cause CSF block
ends up blocking Spinothalamic tract
You lose bilateral pain and temperature sensation!

Question 6

What does the Alternative Thalamic Relay (reticular formation) provide?

Answer 6

Involved in suffering due to pain (no localized pain)