Lecture 10

Question 0

Where does the interaction between the motor unit and the muscle fibres occur?

Answer 0

At the neuromuscular junction

Question 1

The spinal motor circuitry system is a complicated system with a lot of feedback connections, why is this?

Answer 1

Because the motor system needs to excite and inhibit different muscles at together and separately.

Question 2

Name the two different types of descending (cortex to muscle) motor pathways. What is each of there functions?

Answer 2

The Dorsolateral tracts and the ventromedial tracts. The Dorsolateral tracts control independent movements of limbs e.g. Reaching for objects. The ventromedial tracts control limb movements as a whole e.g. Posture.

Question 3

Name the two pathways within the Dorsolateral pathway. And what is there difference.

Answer 3

Direct- corticospinal tract
Indirect- corticobruspinal tract

The difference between them is that the indirect pathway crosses over earlier in the spinal cord at the red nucleus

Question 4

What’s the difference between the indirect and direct pathways in the ventromedial pathway?

Answer 4

The indirect pathway splits into two at the tectum. Both direct and indirect pathways travel ipisilatetally down the spinal cord.

Question 5

In the ventromedial pathway which sub pathway (eg direct or indirect) would have greater plasticity?

Answer 5

The indirect pathway because there are two identical pathways so if one breaks the other is there as backup.

Question 6

What is the function of the cerebellum?

Answer 6

Is involved in balance, speech, coordination and the learning of motor sequences

Question 7

Where does the cerebellum receive it’s input from?

Answer 7

Primary and secondary motor cortexes

Question 8

Where does the cerebellum receive feedback from ?

Answer 8

Somatosensory and vestibular systems

Question 9

What is cerebellar ataxia?

Answer 9

Poor control of gate (walking)

Question 10

What is the role of the basal

Ganglia?

Answer 10

Modulates movement and cognitive functions such as habitual responses and implicit learning

Question 11

Fill in the blanks for the basal ganglia pathway: basal ganglia- ……….. - supplementary motor cortex (secondary)- ……… - feedback

Answer 11

Thalamus

Primary motor cortex

Question 12

What do the direct and indirect pathways of the basal ganglia do? And why are they important?

Answer 12

The direct pathway- excites
The indirect pathway- inhibits
The balance is important to be maintained between direct and indirect pathways otherwise over and under movement behaviours may occur . E.g. Parkinson’s

Question 13

What neural disruption is apparent in Parkinson’s patients?

Answer 13

The loss of dopamine found in the substantia nigra and straitum

Question 14

What is administered to reduce Parkinson’s symptoms? And why?

Answer 14

L-Dopa. Dopamine cannot be administered to patients as it is not taken up by the brain because of the blood brain barrier

Question 15

What are some problems associated with L-Dopa?

Answer 15

L-Dopa can cause serious side effects such as disorientation, confusion and hallucinations. The brain also builds up a tolerance to the drug and will eventually stop working.

Question 16

What are some positive symptoms of Parkinson’s?

Answer 16

Tremors- particularly resting tremors

Rigidity- stiffness of muscles and joints

Question 17

What are some negative symptoms of Parkinson’s?

Answer 17

Reduction in spontaneous movement - hypokinesia
Slow initiation of movement- akinesia
Freezing or slowing during movement
Reduced scale of movement

Question 18

What did Huntington say the 3 peculiarities of huntingtons disease are?

Answer 18

• it’s heredity and found on chromosome 4
• manifests in adults
• tendency for insanity and suicide

Question 19

Explain the progression of signs in huntingtons.

Answer 19

Begins with personality changes- depression, aggression, impulsivity and then progresses to effect the motor system where a lot involuntary movements occur

Question 20

Describe the movement disruption huntingtons patients have ?

Answer 20

Jerky, rapid, uncontrollable movements that come and go randomly. They can resemble voluntary movements

Question 21

Where is the primary motor cortex located?

Answer 21

Precentral gyrus in the frontal lobe.

Question 22

If damage is obtained to this area, what is likely to happen? What is the name for this?

Answer 22

The homunculus is damaged therefore motor performances for particular body parts may be impaired. which is called a hemiplegia

Question 23

What three areas does the secondary motor cortex contain?

Answer 23

Cingulate motor areas, supplementary motor area and the premotor cortex.
PCS.

Question 24

Explain the role of the sensorimotor association area.

Answer 24

The sensorimotor area takes information from the senses and uses it to locate objects and body parts in space.

Question 25

Where is the sensorimotor area?

Answer 25

Posterior parietal lobe

Question 26

If damage is obtained to the input of the sensorimotor area, what is the called and describe it?

Answer 26

Ataxia- the inability to Use visual information to guide hand movements particularly in the peripheral vision.

Question 27

If damage is obtained to the output of the sensorimotor cortex what is this called and explain it?

Answer 27

Apraxia- the inability to pull movements together in an action sequence

Question 28

What is the function of the Dorsolateral prefrontal association cortex and where does it receive information from?

Answer 28

It’s involved in the making of a decision to act. It receives it’s information from the association cortex.

Question 29

Explain the sequence of motor information from the association cortex to the primary motor cortex.

Answer 29

Sensorimotor Association cortex- Dorsolateral prefrontal association cortex/secondary motor area - primary motor area

Question 30

What is ideational apraxia?

Answer 30

Ideational apraxia is the inability to perform complex sequences and actions. Although it can be performed generally in an illogical manner or incorrect order.

Question 31

Ideomotor apraxia is….

Answer 31

The inability to mentally envision and act upon an action.

Question 32

What case study supported the function of the posterior parietal lobe to be those of body part awareness and intrinsic spatial coding?

Answer 32

The case study of a woman who received damage to her parietal lobe and claimed that her arm and leg drifted when they were out of sight

Question 33

Explain the 3 basic components/ states of the motor control system diagram.

Answer 33

The desired or goal state
The actual state (now)
The predicted state (how is should feel)

Question 34

Describe what affordances mean in the motor control system diagram.

Answer 34

Affordances are all the possible stimuli in an environment that can be acted upon. It is the choosing of the correct actions that is important.

Question 35

Why, according to the motor control system diagram, can’t people tickle themselves?

Answer 35

Because people can predict (predicted state) how the tickling will feel so there is no reaction or element of surprise.

Question 36

What is compromised in the alien hand syndrome in the motor control system?

Answer 36

The affordances take over. So all stimuli are reacted upon in the environment. Random grabbing and reaching would occur.

Question 37

What is meant by the mirror neurone system?

Answer 37

When an action is observed, thought of or envisioned the part of the brain that would be stimulated in the performance of the action would also be stimulated.

Question 38

Where is this activation of mirror neurones found?

Answer 38

In the parietal lobes, in the premotor cortex, in the inferior frontal lobe (Broca’s area) and in the superior temporal gyrus.

Question 39

What is the function of these mirror neurone systems?

Answer 39

To understand how to do an action, to understand why others do an action and to plan actions.