Ascending and Descending Pathways

Question 1

What information does the PCML pathway carry?

Answer 1

Discriminative touch, pressure, vibration, conscious proprioception,

Question 2

What terminates in the VPM of the thalamus? What terminates in the VPL?

Answer 2

PCML terminates in the VPL

Trigeminal Chief Sensory Nucleus sends axons to VPM of thalamus

Question 3

What information does the spinothalamic pathway carry?

Answer 3

Pain, temperature, and crude touch

Question 4

What are the two spinocerebellar pathways? What information do they carry and where do they cross?

Answer 4

Posterior spinocerebellar - unconscious proprioception from lower limb and trunk

Cuneocerebellar - unconcsious proprioception from upper limb

**They do not cross midline

Question 5

Anterior corticospinal tract descends spinal cord along the ____________

Answer 5

Anterior funiculus

Question 6

What is the function of the vesitbulospinal pathway?

Answer 6

Excites extensions

Orientation of head and body

Question 7

What is the function of the rubrospinal pathway?

Answer 7

Excites upper limb flexors

Question 8

What is the function of the reticulospinal pathway?

Answer 8

Postural control
Muscle tone
Breathing
Excites extensors

Question 9

What is the function of the tectospinal pathway?

Answer 9

Coordinates head and eye movements

Question 10

Which additional descending pathway is not usually consequential in humans?

Answer 10

Rubrospinal

Question 11

What are the 2 types of posturing in comatose patients, and what causes them?

Answer 11

Decorticate: damage to corticospinal tracts but rubrospinal tract is intact so you get activation of flexors

Decerebrate: damage to corticospinal and rubrospinal tracts - extensor tone because reticulospinal tract is still intact