Cerebellum and Basal Ganglia Flashcards Preview

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Flashcards in Cerebellum and Basal Ganglia Deck (67)
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1
Q

Identify the structure indicated by the arrow

A

Falx cerebri

2
Q

Identify the structure indicated by the arrow

A

Tentorium cerebelli

3
Q

Identify the structure indicated by the arrow

A

Posterior cranial fossa

4
Q

Identify the structure indicated by the arrow

A

Falx cerebelli

5
Q

Identify the structure indicated by the arrow

A

Great cerebral vein

6
Q

Identify the structure indicated by the arrow

A

Tentorium cerebelli

7
Q

Identify the structure indicated by the arrow

A

Primary fissure

8
Q

Identify the structure indicated by the arrow

A

Horizontal fissure

9
Q

Identify the structure indicated by the unlabelled arrow

A

Flocculus

10
Q

Identify all the structures indicated by the arrows on the superior surface of the cerebellum

A
11
Q

Identify all the structures indicated by the arrows on the inferior surface of the cerebellum

A
12
Q

What are the two opposing middle parts in the cerebellum?

A

The tonsils

13
Q

Where are the deep cerebellar nuclei located generally within the cerebellum?

How many are there?

A

Small region of grey matter located in the deep portions of the core of white matter.

There are 4 pairs of deep cerebellar nuclei.

14
Q

How is the cerebellum attached to the brainstem?

A

Via 3 stalks - the peduncles

15
Q

Identify the structures indicated by the arrows

A
16
Q

Which are the largest cerebellar nuclei?

A

The dentate nuclei

17
Q

Which are the most lateral cerebellar nuclei?

A

The dentate nuclei

18
Q

Identify the structures indicated by the arrows

A
  • From lateral to medial:
    • Dentate nucleus
    • Emboliform nucleus
    • Globose nucleus
    • Fastigial nucleus
19
Q

Which is the second largest of the deep cerebellar nuclei and where does it lie?

A

Fastigial is 2nd largest.

It is the most medial.

20
Q

What are the three layers of the cerebellar cortex?

A
  • Molecular layer (outer)
  • Purkinje cell layer (middle)
  • Granule cell layer (inner)
21
Q

Identify the structure indicated by the arrow

A

Molecular layer of the cerebellar cortex

22
Q

Identify the structures indicated by the arrows

A

Purkinje cells in the purkinje cell layer of the cerebellar cortex

23
Q

Identify the structure indicated by the arrow

A

Granular layer of the cerebellar cortex

24
Q

What are the afferents of the cerebellum?

(Projections into the cerebellum)

A
  • From the:
    • Spinal cord (spinocerebellar fibres)
    • Pons (pontocerebellar fibres)
    • Vestibular nuclei (vestibulocerebellar fibres)
    • Inferior olivary nucleus (olivocerebellar fibres)
25
Q

How do the cerebellar afferents reach the cerebellum?

A
  • Climbing fibres from inferior olivary nucleus
  • Mossy fibres from all others
26
Q

Describe the synapse of climbing fibres

A

They sinapse discretely, but extensively on a purkinje cell

27
Q

Describe the synapse of mossy fibres

A

They synapse diffusely on granule cells in the granule cell layer

28
Q

Describe the efferent projections of the cerebellum?

A

From all the lobes of the cerebellum, the only output is via the axons of purkinje cells which synapse on the neurons of the deep cerebellar nuclei (except some flocculonodular purkinje cells, which project directly to vestibular nuclei).

29
Q

What do the efferent projections of the cerebellum do?

A

After synapsing, they subsequently contribute to coordinating the functions of all the motor tracts of the brainstem and spinal cord:

  • Corticospinal
  • Rubrospinal
  • Vestibulospinal
30
Q

Where do most efferent axons from the deep cerebellar nuclei go?

A

Most axons cross the midline and synapse in the thalamus.

The thalamus in turn sends fibres to the motor cortex.

31
Q

Identify the functional areas of the cerebellum

A
  • Striped = Spinocerebellum
  • Black = vestibulocerebellum
  • White = Pontocerebellum
32
Q

What does the vestibulocerebellum consist of?

A
  • Flocculonodular lobe
  • Fastigial nucleus
33
Q

What is the main function of the vestibulocerebellum?

A

Maintaining balance

34
Q

Where does the vestibulocerebellum receive input from?

A

Vestibular nuclei

35
Q

Where do fibres from the vestibulocerebellum project to?

A
  • Reticular formation and vestibular nuclei
    • From there, to the spinal cord via reticulospinal and vestibulospinal tracts
36
Q

What does the spinocerebellum consist of?

A
  • The vermis
  • Globose nuclei
  • Emboliform nuclei
37
Q

What is the main function of the spinocerebellum?

A

Posture and muscle tone

38
Q

Where does the main input to the spinocerebellum come from?

A

Spinocerebellar tracts carrying proprioception, touch and pressure information

39
Q

Where do fibres of the spinocerebellum project to?

A
  • Projects via the deep cerebellar nuclei to the:
    • Thalamus
    • Red nucleus
    • Reticular formation
    • Vestibular nucleus
40
Q

What is the function of the efferents from the spinocerebellum?

A

To influence corticospinal, rubrospinal, reticulospinal and vestibulospinal output

41
Q

What does the pontocerebellum consist of?

A
  • Cerebellar hemispheres
  • Dentate nucleus
42
Q

What is the main function of the pontocerebellum?

A

Muscle coordination

43
Q

Where does the pontocerebellum receive input from?

A

Pontine nuclei, which in turn receive fibres from the cerebral cortex

44
Q

Where do fibres from the pontocerebellum project to?

A
  • Thalamic area (ventral lateral) - that in turn projects to the motor cortex.
  • Red nucleus
45
Q

What are the afferents of the superior cerebellar peduncle?

A
  • Ventral spinocerebellar tract
  • Tectocerebellar fibres
46
Q

What are the efferents of the superior cerebellar peduncle?

A

Cerebellothalamic fibres

47
Q

What are the afferents of the middle cerebellar peduncle?

A

Pontocerebellar fibres (pathway whereby cortex communicates with cerebellum).

48
Q

What are the efferents of the middle cerebellar peduncle?

A

There are none

49
Q

What are the afferents of the inferior cerebellar peduncle?

A
  • Dorsal spinocerebellar tract
  • Olivocerebellar fibres
  • Vestibulocerebellar fibres
50
Q

What are the efferents of the inferior cerebellar peduncle?

A
  • Cerebellovestibular fibres
  • Cerebelloreticular fibres
51
Q

What effect would a midline lesion of the cerebellum have?

A
  • Disturbance of postural control
  • Patient will tend to fall over when standing or sitting depsite preserved limb coordination
52
Q

What effect would a unilateral hemispheric lesion of the cerebellum have?

A
  • Disturbance of coordination of the limbs
  • Can result in intention tremor or unsteady gait in the absence of weakness or sensory loss.
  • Lesions in the cerebellar hemisphere will affect the ipsilateral side.
53
Q

What effect would bilateral cerebellar dysfunction have?

A
  • Slowed, slurred speech - dysarthria
  • Bilateral incoordination of the arms
  • Staggering, wide-based gait - cerebellar ataxia
54
Q

What are the functions of the basal ganglia?

A
  • To facilitate purposeful movement
  • Inhibit unwanted movements
  • Has a role in posture and muscle tone
55
Q

What is the basal ganglia?

A

A number of masses of grey matter located near the base of each cerebral hemisphere.

56
Q

What are the grey matter structures included in the basal ganglia?

A
  • Corpus striatum - a region of grey matter associated with the lateral ventricle. It includes:
    • Striatum which includes:
      • Caudate nucleus
      • Putamen
    • Pallidum:
      • Globus pallidus
  • Subthalamic nucleus
  • Substantia nigra
57
Q

What comprises the Corpus striatum of the basal ganglia?

A
  • Caudate nucleus
  • Putamen
  • Globus pallidus
58
Q

What comprises the striatum of the basal ganglia?

A

The caudate nucleus and the putamen

59
Q

What are the 5 structures within the basal ganglia?

A
  • Caudate nucleus
  • Putamen
  • Globus palllidus
  • Subthalamic nucleus
  • Substantia nigra
60
Q

Identify the structure indicated by the arrow

A

Substantia nigra

61
Q

What are the afferents of the striatum (caudate nucleus and putamen)?

A
  • The striatum receives input from:
    • Cerebral cortex (corticostriatal)
    • Thalamus (thalamostriatal)
    • Substantia nigra (nigrostriatal)
  • Shown in blue
62
Q

What are the efferents of the striatum (caudate nucleus and putamen)?

A
  • The striatum sends fibres to:
    • Globus pallidus (striatopallidal)
    • Substantia nigra (striatonigral)
  • Shown in red
63
Q

What are the afferents of the globus pallidus?

A
  • Globus pallidus receives fribres from:
    • Striatum (striatopallidal)
    • Subthalamic nucleus (subthalamopallidal)
  • Shown in blue
64
Q

What are the efferents of the globus pallidus?

A
  • Globus pallidus sends fibres to:
    • Thalamus (palladothalamic)
    • Subthalamic nucleus (pallidosubthalamic)
    • Pons
  • Shown in red
65
Q

Which area would unilateral lesions of the basal ganglia affect?

A

The contralateral side of the body.

They generally do no cause paralysis, sensory loss, loss of power or ataxia.

66
Q

What motor symptoms do lesions of the basal ganglia cause?

A
  • Abnormal muscle control (bradykinesia)
  • Changes in muscle tone
  • Dyskinesias (abnormal involuntary movements) including:
    • Tremor
    • Chorea (rapid, asymmetrical movements usually affecting distal limb musculature)
    • Myoclonus (muscle jerks)
67
Q

What are some of the disorders associated with the basal ganglia?

A
  • Parkinson’s disease
  • Huntington’s disease