Modulation of Movement: Basal Ganglia and Cerebellum Flashcards Preview

MD1 Neuroscience > Modulation of Movement: Basal Ganglia and Cerebellum > Flashcards

Flashcards in Modulation of Movement: Basal Ganglia and Cerebellum Deck (53):
1

What does the motor cortex do?

Initiation of voluntary movement
Skilled, dexterous movements
Integration of movement with
- Maintenance of postural stability
- Goals
- Physical environment

2

What kind of motor patterns does the motor cortex coordinate?

Extended patterns of movement

3

Does the motor cortex exert ipsilateral or contralateral control of the body?

Contralateral

4

Where is the motor cortex located?

Pre-central gyrus

5

What happens when areas more rostral to the motor cortex are stimulated?

More complex movements produced

6

What is the topographical mapping of the motor cortex?

Lower limb medial
Upper limb more lateral
- Fingers and hands have large areas
Head and face lateral
- Large area from lips and mouth

7

What areas of the cortex are activated with simple movement?

Pre-central gyrus
Post-central gyrus in similar area

8

What areas of the cortex are activated with complex movement?

Pre-central gyrus
Post-central gyrus in similar area
Pre-motor areas

9

What areas of the cortex are activated with mental rehearsal of complex movment?

Motor association area only

10

What is really represented in the primary motor cortex?

Wherever hand is at start of stimulation of cortex, activation of area of motor cortex moves hand to particular region
Produces ecologically logical movements

11

Describe the experiment that demonstrates what mirror motor neurons are

Neurons would fire when monkeys observed experimenters doing things
These neurons recognised those tasks
When monkey performed same task, same neuron fires as well

12

What do mirror motor neurons recognise?

Same pattern of movements rather than same end goal

13

What is the likely reason for the existence of mirror motor neurons?

How we learn - people and monkeys learn a lot of things by watching

14

Where are the inputs to the primary motor cortex from

Association areas
Somatosensory cortex
Posterior parietal area

15

What does the posterior parietal area do?

Synthesises sensory information into egocentric map

16

Where do the pre-motor areas receive input from?

Posterior parietal areas
Pre-frontal areas responsible for salience of objects and tasks
- Goal driving
- Planning

17

What are the visual streams coming into the motor areas?

Dorsal
Ventral

18

What do the visual streams provide information to the motor cortex on?

Where things are
What things are

19

What types of movement do the visual streams "control"?

Dorsal = where > reach
Ventral = what > grasping - hand shaping

20

What are the functions of the basal ganglia?

Allow selection of complex patterns of voluntary movements
Evaluate success of actions in achieving goals of actions
Initiating movements

21

What is the relationship between the basal ganglia and motor cortex?

Basal ganglia modulate what happens in motor cortex

22

How do the basal ganglia project to the motor cortex?

Only via thalamus

23

Do the basal ganglia project to other cortical regions?

Yes

24

Which basal ganglia is destroyed in Parkinson's disease?

Substantia nigra

25

With what level of damage to the substantia nigra do clinical signs of Parkinson's disease appear?

80% of neurons lost

26

Why is the substantia pigmented black?

Presence of black pigment melanin in dopaminergic neurons

27

What basal ganglia are affected in Huntington's disease?

Caudate
Lenticular nucleus

28

What are the characteristics of the Parkinsonian gait?

Stooped posture
Turning by small shuffling steps
Tremor in limbs
Bradykinesia

29

What is the role of dopamine in the basal ganglia?

Facilitates pathway of information from basal ganglia to motor cortex

30

What are the characteristics of chorea in Huntington's disease?

Quick irregular involuntary muscle twitches
Hyperactivity of hands, feet, and sometimes entire limb

31

Where does input from the motor cortex come into the basal ganglia?

Striatum

32

How many pathways are there from the basal ganglia to the motor cortex?

Two, via thalamus

33

Describe the direct pathway from the basal ganglia to the motor cortex?

Facilitates movements
Selects movement patterns to go together to make coherent motor plan
Facilitated by dopamine
Removes inhibition

34

Describe the indirect pathway from the basal ganglia to the motor cortex?

Stops movement from happening, especially those that interfere with those that are happening
Excites inhibitory neurons to inhibit these pathways
Dopamine reduces activity

35

What is the role of having both a direct and indirect pathway?

Movements selected stand out more clearly by inhibiting all others

36

What are the functions of the cerebellum?

Coordinating timing and sequence of muscle actions and movements
Maintenance of tone
Motor learning
Planning sequences of muscle activation for complex movements

37

What inputs does the cerebellum receive?

Copies of motor commands from motor cortex
Ascending information to see how motor command went

38

What does the cerebellum do with the information it receives from the motor cortex and ascending information?

Compares two to adjust movement

39

What cortical structures does the cerebellum link with?

Primary and associated motor cortices

40

What is the gross structure of the cerebellum?

Tightly folded
Three lobes
Cerebellar peduncles attach it to brainstem

41

Where do fibres in the cerebellar peduncles connect to?

Medulla
Pons
Midbrain

42

What is the functional organisation of the cerebellum?

Approx medial to lateral

43

What is ataxia?

Inability to appropriately integrate/coordinate movement

44

What happens with a lesion in the cerebellum?

Ataxia

45

Does a unilateral lesion in the cerebellum have a contralateral or ipsilateral effect?

Generally ipsilateral

46

What is anterior lobe syndrome?

Ataxic gait
Loss of inter-limb coordination

47

Why does anterior lobe syndrome occur?

Chronic ethanol toxicity > anterior Purkinje cells in cerebellum preferentially lost

48

How does anterior lobe syndrome progress?

Progression of pathology posterioly involves upper limbs and facial muscle dys-coordination

49

What is posterior lobe syndrome?

Dysemtria
Dysdiadochokinesia
Speech abnormality
- Loss of natural rhythm
- Slurring across syllables
- Overcompensation by explosive speech

50

What is dysemtria?

Overshoot in precision speech

51

What is dysdiadochokinesia?

Inability to rapidly alternate movements

52

What is flocculonodular lobe syndrome?

Truncal ataxia
- Difficulty walking
- In severe cases: difficulty standing and sitting

53

Why are cerebellar lesions ipsilateral to deficits?

One side of cerebellum sends output > crosses midline > info received by contralateral motor cortex
Motor cortex sends information to body on contralateral side
= double cross

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