Neuro - Motor Control

Question 1

What is hierarchical organisation?

Answer 1

High orders areas are involved in more complex tasks, low level areas of hierarchy perform lower level tasks

Question 2

What is functional segregation?

Answer 2

Motor systems organised in a number of different aspects of movement

Question 3

What are the major descending tracts?

Answer 3

Pyramidal - pass through pyramids of the medulla
E.g. corticospinal and corticobulbar
Output neurons in motor cortex to spinal cord or cranial nuclei in brain stem

Extrapyramidal - do not pass through the pyramids of the medulla
E.g. vestibulospinal, tectospinal, reticulospinal, rubrospinal
Output neurons from brainstem nuclei to spinal cord

Question 4

What is the function of the corticobulbar tract?

Answer 4

Motor pathway for voluntary movement of the face (and neck)

Question 5

What is the function of the vestibulospinal tract?

Answer 5

Stabilise the head during by movements or as head moves
Coordinate head movements with eye movements
Mediate postural adjustment

Question 6

What is the function of the reticulospinal tract?

Answer 6

Changes in muscle tone associated with voluntary movement

Postural stability

Question 7

What is the function of the tectospinal tract?

Answer 7

Orientation of the head and neck during eye movements

Question 8

What is the function of the rubrospinal tract?

Answer 8

In humans mainly taken over by the corticospinal tract

Inner gate lower motor neurons of flexor of the upper limb

Question 9

What are the negative and positive signs of a upper motor neurone lesion?

Answer 9

Negative signs:
Loss of voluntary motor function
Paresis: graded weakness of movements
Paralysis(plegia): complete loss of voluntary muscle activity

Positive signs:
Increased abnormal motor function due to loss of inhibitory descending inputs
Spasticity: increased muscle tone
Hyper-reflexia: exaggerated reflexes
Clonus: abnormal oscillatory muscle contraction
Babinski’s sign

Question 10

What is apraxia?

Answer 10

A disorder of skilled movement

Question 11

Effects of a lower motor neuron lesion?

Answer 11

Weakness
Hypotonia
Hyporeflexia 
Muscle atrophy
Fasiculations
Fibrillation

Question 12

What makes up the basal ganglia.

Answer 12

Caudate nucleus
Lentiform nucleus
Nucleus accumbens
Subthalamic nuclei
Substantia nigra
Ventral pallidum, claustrum, nucleus basalis

Question 13

What is the function of the basal ganglia?

Answer 13

Decision to move
Elaborating associated movements - walking: arms and legs
Moderating and coordinating movement
Performing movements in order

Question 14

What are the symptoms of Parkinson’s disease?

Answer 14

Bradykiensia - slowness of small movements
Hypomimic face - expressionless
Akinesia - difficulty in initiation of movements because cannot initiate movements internally
Rigidity - muscle tone increase, causing resistance to externally imposed joint movement
Tremor at rest - 4-7 Hz in one hand (pill rolling tremor); travels to other parts of the body over time

Question 15

What is the cause of Huntington’s disease?

Answer 15

Degeneration of GABAergic neurons in the striatum, caudate and then put amen

Question 16

What are the main signs of cerebellar dysfunction?

Answer 16

Ataxia
Dysmetria
Intention tremor
Dysdiadochokinesia
Scanning speech