22 - Neural Control of Movement Flashcards Preview

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Flashcards in 22 - Neural Control of Movement Deck (22):
1

What is the difference in the function of upper and lower motor neurones?

Lower motor neurones produce muscle contractions via motor units
Upper motor neurones produce voluntary movements

2

What is the main function of the cerebellum?

Coordinate muscle movements and select correct sequences

3

What is the main function of the basal ganglia?

Initiation and maintenance of movements containing the motor programs

4

What are the 3 motor pathways that upper motor neurons contribute to?

- Corticospinal tract
- Rubrospinal tract
- Vestibulospinal and reticulospinal tract

5

Where are the cell bodies of upper motor neurons found?

Cerebral cortex and brainstem

6

What are 5 functions of upper motor neurones?

- Inhibition
- Reflex modulation - modulate intensity
- Efference copy
- Activation of other brainstem UMN (reticular formation, red nucleus)

7

What are the corticospinal, rubrospinal and vestibulospinal and reticulospinal tracts?

- Corticospinal
From the cerebral cortex to the spinal cord
Precise movements
- Rubrospinal
From the brainstem to the spinal cord
Gross movements
Facilitates flexor movements
- Vestibulospinal and reticulospinal
From the brainstem to the spinal cord
Posture and balance - mainly trunk muscles

8


Draw a diagram representing the organisation and location of UMN pathways

- Look at google docs

9

What is the role of the motor cortex?

To know where the body is in space, where it intends to go and the selection of a plan of how to get there

10

Label the picture A-D
- Look at google docs

A - pre-frontal cortex
B - frontal eye fields
C - Pre-motor cortex and supplementary cortex
D - Primary motor cortex

11

What are the decision, planning and action cortex?

Decision - Posterior parietal cortex (areas 5 and 7)
Planning - Association motor cortex (area 6)
Action - Primary motor cortex (area 4)

12

What are the divisions of the cerebellum? What does each division do?

- Vestibulo-cerebellum
Balance and posture
Eye movements
- Spino-cerebellum
Locomotion
Voluntary movements of arms and legs
- Cerebro-cerebellum
Skilled motor tasks
Speech, hand-eye coordination, cognitive eye movements

13

What is the brake theory?

To keep still - put the brake on all movements (except reflexes to maintain posture)
To move - apply brake to some postural reflexes and release brake on voluntary movement
Basal ganglia - take the brake off in both situations

14

What are the 5 nuclei of the basal ganglia?

Caudate
- Putamen
- Globus pallidus
- Substantia nigra
- Subthalamic nuclei

15

What is muscle tone?

Tension in the muscle due to partial state of contraction

16

How is muscle tone maintained?

Reflexively - stretch and GTO reflexes and gamma motor neurones
Also adjusted by descending motor pathways

17

How is tone and posture related?

- Most of the body weight is anterior to the vertebral column
- Deep muscles of the back are therefore important in maintaining postural stance
- Antigravity muscles are more developed and have greater tone

18

What occurs if there is damage to the cerebellum?

- Ataxia: Complete lack of integration of the sequences of movements(complete incoordination) and hypotonia

19

What happens if there is damage to the basal ganglia?

Slowing or unwanted movements (hyper/hypokinesia)

20

What happens if there is damage to the association motor cortex?

Apraxia: unable to execute familiar learned movements in absence of sensorimotor dysfunction

21

What happens if there is damage to the descending pathways?

Spasticity and hypertonia due to lack of inhibition from UMN

22

What is the definition of Spasticity, rigidity and flaccidity?

Spasticity - Increased muscle tone due to the loss of inhibition of gamma motor neurones
Rigidity - Increases muscle tone due to the loss of inhibition of alpha motor neurones
Flaccidity (hypotonia) - Decreased muscle tone to the nerve or LMNs damage