Overview of Central Sensory and Motor Pathways

Question 1

What can the cerebral cortex be divided into and what by?

Answer 1

• Motor brain
• Sensory brain
• Separated by central sulcus

Question 2

Which lobes make up each division of the cerebral cortex?

Answer 2

• M = frontal lobe
• S = parietal, occipital, temporal lobes

Question 3

2 medio-lateral chunks of brain tissue separated by the central sulcus?

Answer 3

• Pre-central gyrus
• Post-central gyrus

Question 4

Order that sensory information is carried through the ascending tracts

Answer 4

• Spinal cord (dorsal horn)
• Medulla
• Thalamus
• Cerebral cortex

Question 5

Where is sensory information first processed in the cerebral cortex?

Answer 5

Post-central gyrus

Question 6

What are ascending tracts?

Answer 6

Fibre tracts of the sensory system by which sensory information is conveyed from the spinal cord to the brain

Question 7

Ascending tracts in the spinal cord

Answer 7

• Ventral spinocerebellar tract
• Dorsal spinocerebellar tract
• Spinothalamic tract
• Fasciculus proprius
• Fasciculus cuneatus
• Fasciculus gracilis

Question 8

2 categories of sensation

Answer 8

• Conscious sensation
• Non-conscious sensation

Question 9

What sensations are conscious sensations?

Answer 9

• Pain
• Temperature
• Crude touch

Question 10

What sensations are non-conscious sensations?

Answer 10

• Tactile sensation
• Muscle length
• Muscle tension
• Joint position

Question 11

What does a primary sensory neurone do when it reaches the spinal cord?

Answer 11

• Divides into 3 branches
• 1 axonal process terminates in the dorsal horn of its respective spinal segment
• The other 2 go to the dorsal horns above and below

Question 12

In what do the axonal segments travel to the spinal segments above and below?

Answer 12

Posterolateral tract of Lissauer

Question 13

3 stages of spinal sensation

Answer 13

• 1 = sensory neurone carries signal to grey matter of dorsal horn
• 2 = second-order sensory neurone carries signal across midline to travel on opposite side of spinal cord to the thalamus
• 3 = third-order sensory neurone carries signal to post-central gyrus

Question 14

What causes syringomyelia and what are the symptoms?

Answer 14

• CSF-filled cyst forms within the central canal of the spinal cord, damaging sensory fibres
• Clinical signs of bilateral anaesthesia

Question 15

What are voluntary motor commands of the brain to muscles issued through?

Answer 15

Pre-central gyrus

Question 16

Order that motor information is carried through the descending tracts

Answer 16

• Cerebral cortex
• Thalamus
• Basal ganglia
• Spinal cord (ventral horn)

Question 17

2 classes of descending tract and where do they originate?

Answer 17

• Cortical descending tracts = pre-central gyrus
• Non-cortical descending tracts = midbrain, pons, medulla

Question 17

Through what nerve are most sensory signals of the head and neck conveyed to the brain?

Answer 17

Trigeminal nerve (CNV)