Cortical motor function

Question 1

How is the Motor system organised?

Answer 1

Into a number of different areas that control different aspects of movement

Question 2

Explain the hierarchical organisation of motor control

Answer 2

High order areas of hierrachy are involved in more complex tasks
Lower level areas of hierarchy perform lower level tasks (excecution of movement)

Question 3

What is the function of the primary motor cortex?

Answer 3

Control fine, discrete, precise voluntary movement

Provides descending signals to execute movement

Question 4

What does the motor cortex consist of?

Answer 4

Primary motor cortex
Premotor cortex
Supplementary motor area

Question 5

What does the association cortex consist of?

Answer 5

Parietal and frontal cortex

Question 6

What does the brainstem do?

Answer 6

Centre of integration of different inputs coming from the vestibular, vision and auditory systems

Question 7

What does the motor cortex do?

Answer 7

It is where movements are programmed and where the voluntary movements are initiated

Question 8

What does the association cortex do?

Answer 8

It influences the planning and execution of movements

Question 9

Where is the location of the primary motor cortex?

Answer 9

Precentral gyrus, anterior to the central sulcus

Question 10

Where is the location of the premotor cortex?

Answer 10

Frontal lobe, anterior to M1

Question 11

What is the function of the premotor cortex?

Answer 11

Planning of movements

Regulates externally cued movements

Question 12

Where is the location of the supplementary motor area?

Answer 12

Frontal lobe anterior to M1, medially

Question 13

What is the function of the supplementary motor area?

Answer 13

Planning complex movements; programming sequencing of movements
Regulates internally driven movements
SMA becomes active when thinking about a movement before executing that movement

Question 14

What is the function of the posterior parietal cortex?

Answer 14

Ensures movements are targeted accurately to objects in external space

Question 15

What is the function of the prefrontal cortex?

Answer 15

Involved in selection of appropriate movements for a particular course of action

Question 16

What is paresis?

Answer 16

graded weakness of movements

Question 17

What is paralysis?

Answer 17

complete loss of muscle activity

Question 18

What is spasticity?

Answer 18

Increased muscle tone

Question 19

What is hyperreflexia?

Answer 19

exaggerated reflexes

Question 20

What is a clonus?

Answer 20

abnormal oscillatory muscle contraction

Question 21

What is apraxia?

Answer 21

A disorder of skilled movement. Patients are not peretic but have lost information about how to perform skilled movements

Question 22

Apraxia is caused by a lesion of…

Answer 22

…inferior parietal lobe, frontal lobe (premotor cortex, supplementary motor area)

Question 23

What are the most common causes of apraxia?

Answer 23

Stroke, dementia

Question 24

Lower motor neurone lesions affect which motor neurone?

Answer 24

The 2nd motor neurone (the one that starts in the grey matter of the spinal cord and exits to form peripheral nerves

Question 25

List the signs of lower motor neurone lesions

Answer 25

``` Weakness Hypotonia Hyporeflexia Muscle atrophy Fasciculations Fibrillations ```

Question 26

What is hypotonia?

Answer 26

Reduced muscle tone

Question 27

What is hyporeflexia?

Answer 27

Reduced reflexes

Question 28

What is meant by fasciculations?

Answer 28

Damaged motor units produce spontaneous action potentials, resulting in a visible twitch

Question 29

What is meant by fibrillations?

Answer 29

Twitch of individual muscle fibres - these aren't visible to the naked eye but can be recorded if the patients have needle electromyography

Question 30

Motor neurone disease can affect which neurones?

Answer 30

Only upper motor neurones Only lower motor neurones Both

Question 31

When MND affects both upper and lower motor neurones, it is called...

Answer 31

...Amyotrophic lateral sclerosis

Question 32

Listthe signs of ALS

Answer 32

``` Increased muscle tone Brisk limbs and jaw reflexes Babinski's sign Loss of dexterity Dysarthria - difficulty with their speech Dysphagia ```

Question 33

List the upper motor neurone signs of MND

Answer 33

``` Increased muscle tone Brisk limbs and jaw reflexes Babinski's sign Loss of dexterity Dysarthria - difficulty with their speech Dysphagia ```

Question 34

List the lower motor neurone signs of MND

Answer 34

``` Weakness Muscle wasting Tongue fasciculations and wasting Nasal speech Dysphagia ```

Question 35

What does the basal ganglia consist of?

Answer 35

Caudate nucleus Lentiform nucleus (putamen & external globus pallidus) Subthalamic nucleus Substantia nigra Ventral pallidum, claustrum, nucleus accumbens, nucleus basalis of Meynert