Motor Control

Question 1

Primary motor cortex

Answer 1

Highest level
Projects directly to spinal cord or via corticospinal tract
Regulates the motor tracts that originate in the brainstem

Question 2

Brainstem

Answer 2

Middle level
Lateral descending system controls distal limbs
Is important for goal-directed movements of hand and arm

Question 3

Spinal Cord

Answer 3

Lowest level

Contains neuronal circuits that mediate reflexes such as walking

Question 4

What is the simplest refelx?

Answer 4

Monosynaptic-sensory neurone and motor neurone

Question 5

What are most reflexes?

Answer 5

Polysynaptic with interneurones

Question 6

What happens if you artificially stimulate the motor cortex?

Answer 6

Get twitches from the motor areas (simple vowel sounds in the speech motor areas)

Question 7

Why can babies not walk?

Answer 7

Their corticospinal tracts are not yet myelinated

Question 8

Basal ganglia and cerebellum

Answer 8

Receive information from many different areas of the cortex and project to motor cortex via thalamus
They are aware of situation the person is in and they monitor commands going down to the muscles to make sure they are appropriate

Question 9

What happens if the commands are not appropriate?

Answer 9

The basal ganglia and cerebellum step in and calculate correction signals to send back up to the motor cortex for approval before the correction signal is sent to the muscles

Question 10

Basal ganglia loop only feeds back to ______

Answer 10

The motor cortex

Question 11

Cerebellum mainly feeds back to ______ but it can send signals down the _____, _____ and onto ____

Answer 11

Motor cortex
Brainstem
Spinal cord
Muscles

Question 12

Which part acts in an emergency?

Answer 12

The cerebellum as it has the ability to bypass the motor cortex for permission and send the signal anyway

Question 13

What did Wilder Penfield do?

Answer 13

He was a neurosurgeon who woke patients up during procedures and artificially stimulated parts of the brain to see what they did
He mapped out motor map of the brain by correlating anatomical stimulation and clinical observations on effects of lesions

Question 14

Where is the motor cortex located?

Answer 14

Just before the central sulcus

Question 15

What is the motor cortex sometimes called?

Answer 15

The precentral gyrus

To highlight its position

Question 16

Along the motor cortex there is a orderly representation of the ____

Answer 16

Human body

Question 17

Why is the finger area so widespread in terms of evolution?

Answer 17

So that damage doesn’t have such a big effect, and you can still use your hands for things for survival like eating etc

Question 18

The motor cortex’s first neurones are called…?

Answer 18

The upper motor neurones

Question 19

What do UMNs carry?

Answer 19

Motor commands down through the brain, brainstem and to the spinal cord

Question 20

Where do the UMNs output and via what?

Answer 20

Output to the lower motor neurones via interneurones

Question 21

What are the UMNs involved in?

Answer 21

The planning, initiation and direction of movements

Question 22

What are older UMNs in the brainstem involved in?

Answer 22

Regulation of muscle tone
Posture
Maintaining balance
Orientation of the head and body

Question 23

Upper Motorneurone pathways

Answer 23

Direct pathways

Indirect pathways

Question 24

Direct motor pathways

Answer 24

Input to LMN from axons extending directly from cerebral cortex

Question 25

Indirect motor pathways

Answer 25

Input to LMN from motor centres in the brainstem

Question 26

What do both direct and indirect pathways govern?

Answer 26

Production of action potentials in LMN

Final common pathway that leads to muscle contraction/movement

Question 27

What does the basal ganglia consist of?

Answer 27

Caudate 
Putamen 
Globus pallidus
Substantia nigra 
Subthalamic nuclei

Question 28

What does the basal ganglia do?

Answer 28

Helps initiate and terminate movements
Suppresses unwanted movements
Establishes normal level of tone

Question 29

What does the cerebellum do?

Answer 29

Monitors movements for differences in intended and actual movements
Sends an error signal and tries to reduce discrepancy
Slipping over and correcting posture