ascending tracts

Question 1

Describe what an ascending tract is

Answer 1

Sensory info from peripheral nerves transmitted to the cerebral cortex
Can be divided into conscious and unconscious tracts

Question 2

What are the conscious tracts?

Answer 2

DCML (dorsal column-medial lemniscal pathway)
Anterolateral system

Question 3

What are the unconscious tracts?

Answer 3

Spinocerebellar tracts

Question 4

What does the DCML tract carry?

Answer 4

Sensory modalities of fine touch, vibration and proprioception

Question 5

Where does the DCML go?

Answer 5

Dorsal column-medial lemniscal pathway:

Travels in the dorsal columns in the spinal cord
Goes through the medial lemniscus in the brainstem

Question 6

Describe the path of 1st order neurones carrying sensory information from the upper limb (T6 and above) in the DCML

Answer 6

• Travel in the fasciculus cuneatus (lateral part of dorsal column)
• Synapse in the nucleus cuneatus of the medulla oblongata

Question 7

Describe the path of 1st order neurones carrying sensory information from the lower limb (below T6) in the DCML

Answer 7

• Travel in the fasciculus gracilis (medial part of dorsal column)
• Synapse in the nucleus gracilis of medulla oblongata

Question 8

Describe the decussation of neurones in the DCML

Answer 8

2nd order neurones decussate in the medulla oblongata

Question 9

Where do 2nd order neurones go to in the DCML?

Answer 9

Decussate in the medulla oblongata, travel in contralateral medial lemniscus to reach the thalamus

Question 10

Describe 3rd order neurones in the DCML

Answer 10

Transmit sensory signals from the thalamus to the ipsilateral primary sensory cortex

Travel through the internal capsule

Question 11

What are the 2 tracts in the anterolateral system?

Answer 11

Anterior spinothalamic tract

Lateral spinothalamic tract

Question 12

What sensations does the anterior spinothalamic tract carry?

Answer 12

Crude touch and pressure

Question 13

What sensations does the lateral spinothalamic tract carry?

Answer 13

Pain and temperature

Question 14

Describe the path of the 1st order neurones in the anterolateral tracts

Answer 14

Arise from sensory receptors in the periphery
Enter spinal cord, ascend 1-2 vertebral levels and synapse at the tip of the dorsal horn

Question 15

Describe the path of 2nd order neurones in the anterolateral system

Answer 15

After synapsing with 1st order neurones, these fibres decussate within the spinal cord and form 2 tracts:

Crude touch and pressure: anterior spinothalamic tract
Pain and temperature: lateral spinothalamic tract

Travel up the spinal cord and synapse in the thalamus

Question 16

3rd order neurones in the anterolateral system

Answer 16

Carry sensory signals from the thalamus to the ipsilateral primary sensory cortex

Question 17

What are the 4 spinocerebellar tracts?

Answer 17

Posterior spinocerebellar tract

Cuneocerebellar tract

Anterior spinocerebellar tract

Rostral spinocerebellar tract

Question 18

What does the posterior spinocerebellar tract carry and to where?

Answer 18

Proprioceptive info from the lower limbs to the ipsilateral cerebellum

Question 19

What does the cuneocerebellar tract carry and to where?

Answer 19

Proprioceptive information from upper limbs to ipsilateral cerebellum

Question 20

What does the anterior spinocerebellalr tract carry and to where?

Answer 20

Carries proprioceptive information from lower limbs.

Fibres decussate twice so terminate in ipsilateral cerebellum

Question 21

What does the rostral spinocerebellar tract carry and to where?

Answer 21

Proprioceptive info from upper limbs to the ipsilateral cerebellum

Question 22

What would brown-sequard syndrome do?

Answer 22

Hemisection (one sided lesion) of the spinal cord

DCML pathway - decussates in medulla oblongata - ipsilateral loss of touch, vibration and proprioception

Anterolateral system - decussates in spinal cord - contralateral loss of pain and temperature sensation

Descending motor tracts - ipsilateral hemiparesis