Cerebellum and Basal Ganglia

Question 1

Where is the cerebellum located?

Answer 1

Posterior and inferior to the cerebral hemispheres

Below the tentorium cerebelli

Question 2

What are the lobes of the cerebellum?

Answer 2

Anterior
Posterior
Flocculonodular

Question 3

What fissure separates the anterior and posterior lobes of the cerebellum?

Answer 3

Primary fissure

Question 4

What fissure separates the posterior and flocculonodular lobes of the cerebellum?

Answer 4

Posterolateral fissure

Question 5

What attaches the cerebellum to the brainstem?

Answer 5

Peduncles (superior, middle, inferior)

Question 6

What is the name of gyri in the cerebellum?

Answer 6

Folia

Question 7

Where are the cerebellar nuclei and what is there function?

Answer 7

Deep grey matter
Send information to the brainstem and thalamus which can influence areas of the motor cortex or the descending tracts to modify movements

Question 8

What are the 3 layers of the cerebellar cortex?

Answer 8

Molecular (outer)
Purkinje (middle)
Granule (inner)

Question 9

Where do afferent projections to the cerebellum mainly project to?

Answer 9

Granule cell layer

Question 10

What structure do the purkinje cells communicate with?

Answer 10

Deep cerebellar nuclei

Question 11

The only output of the cerebellum is via axons of ____ cells

Answer 11

Purkinje

Question 12

What are the functional divisions of the cerebellum?

Answer 12

Pontocerebellum (conscious movement)
Spinocerebellum (automatic function e.g. posture)
Vestibulocerebellum (equilibrium balance and posture) (flocculonodular lobe)
Vermis (posture, limb movement and eye movement)

Question 13

Cerebellar hemispheres influence ipsilateral/contralateral side of the body

Answer 13

Ipsilateral

Question 14

What does a unilateral cerebellar hemispheric lesion cause?

Answer 14

Disturbance of coordination in limbs

Can result in intention tremor and unsteady gait (in the absence of weakness or sensory loss)

Question 15

What does bilateral cerebellar hemispheric dysfunction cause?

Answer 15

Results in slowed, slurred speech (dysarthria), bilateral incoordination of the arms and staggering wide based gait (cerebellar ataxia)
Acute alcohol exposure typically results in bilateral cerebellar hemisphere dysfunction and presents with cerebellar ataxia

Question 16

What does a midline cerebellar lesion cause?

Answer 16

Disturbances to postural control

Patients will tend to fall over when standing or sitting despite preserved limb coordination

Question 17

What are the basal ganglia and where are they located?

Answer 17

Masses of grey matter located near the base of each cerebral hemisphere

Question 18

Name the parts of the basal ganglia

Answer 18

Caudate nucleus
Putamen
Globus pallidus
Subthalamic nucleus
Substantia nigra

Question 19

Name the basal ganglia that make up the striatum

Answer 19

Caudate nucleus

Putamen

Question 20

Name the basal ganglia that make up the corpus striatum

Answer 20

Caudate nucleus
Putamen
Globus pallidus

Question 21

Name the basal ganglia that make up the lenitucular nucelus

Answer 21

Putamen

Globus pallidus

Question 22

Which basal ganglia has a black strip and why is it black?

Answer 22

Substantia nigra

Produces dopamine and a black biproduct

Question 23

What does the internal capsule separate?

Answer 23

Separates the caudate nucleus and the thalamus from the putamen and the globus pallidus

Question 24

What are the functions of the basal ganglia? (3)

Answer 24

To facilitate purposeful movement
Inhibit unwanted movements
Role in posture and muscle tone

Question 25

What is an inhibitory neuron?

Answer 25

A neuron that releases neurotransmitter that inhibits the next neuron

Question 26

What are the main input nuceli of the basal ganglia?

Answer 26

Caudate nucleus

Putamen

Question 27

What are the main output nuceli of the basal ganglia?

Answer 27

Globus pallidus

Substantia nigra

Question 28

________ has inhibitory neurons which inhibit the thalamus to prevent unwanted movements

Answer 28

Globus pallidus

Question 29

What does the direct pathway do?

Answer 29

Enhances the outflow of the thalamus, enhancing the desired movement
(silencing of neurons in the globus pallidus so the thalamus is no longer inhibited and movement can occur)

Question 30

What does the indirect pathway do?

Answer 30

Inhibits the outflow of the thalamus

Involves the subthalamic nucleus which leads to suppression of unwanted movements by inhibiting the thalamus

Question 31

Unilateral lesions of the basal ganglia affect the contralateral/ipsilateral side of the body

Answer 31

Contralateral

Question 32

What symptoms do lesions of the basal ganglia cause?

Answer 32

Changes in muscle tone

Dyskinesias (abnormal, involuntary movements): tremor, chorea, myoclonus

Question 33

What 2 disorders are associated with the basal ganglia?

Answer 33

Parkinson’s disease

Huntington’s disease