Functional Hierarchy of the Motor System

Question 1

The brainstem nuclei are controlled by and receive input regarding voluntary movements from

Answer 1

higher brain centres e.g. cerebral cortex, basal ganglia and cerebellum

Question 2

What four systems control movement?

Answer 2

Descending control pathways
Basal ganglia
Cerebellum and local spinal cord
Brain stem circuits

Question 3

Function of lower motor neurones

Answer 3

Directly innervate muscles at cranial and spinal levels to initiate reflex and voluntary movements

Question 4

Function of upper motor neurones

Answer 4

Synapse with multiple lower circuit neurones to regulate alpha-motoneurone activity and control spatiotemporal skilled movements

Question 5

LMN lesions cause

Answer 5

flaccid paralysis and muscle atrophy

Question 6

UMN lesions cause

Answer 6

spasticity, some paralysis

Question 7

Lesions in many posture-regulating pathways will result in

Answer 7

spastic paralysis

Question 8

Corticospinal lesions will result in

Answer 8

weakness rather than paralysis

Question 9

What is the final common pathway?

Answer 9

The motor neurone pools of LMN by which nerve impulses from many central sources pass to a muscle or gland in the periphery

Question 10

What are the immediate sensory and autonomic effects of spinal cord transection?

Answer 10

Loss of sensation

Loss of bowel, bladder and sexual regulation

Question 11

What additional consequences of spinal cord transection will be present in spinal shock?

Answer 11

Loss of supraspinal excitation

Reflexes not evoked

Question 12

What might be the consequence of spinal cord transection on the reflexes?

Answer 12

Reflexes become exaggerated

Question 13

What is Babinski’s sign?

Answer 13

An upward response of extension when the sole of the foot is stimulated with a blunt instrument

Question 14

What might Babinski’s sign indicate in adults?

Answer 14

UMN lesions causing damage to the corticospinal tract