Cerebellum and Basal Ganglia

Question 1

Embryologically the cerebellum is an extension of the _______

Answer 1

Pons

Question 2

Describe the lobes of the cerebellum

Answer 2

There is an anterior lobe, a much bigger posterior lobe and a flocculonodular lobe

Question 3

How is the cerebellum attached to the brainstem?

Answer 3

By stalks called peduncles which are white matter tracks

There is a superior cerebellar peduncle, a middle cerebellar peduncle and an inferior cerebellar peduncle

Question 4

The cerebellar cortex is divided into 3 layers which are?

Answer 4

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

Question 5

Describe afferent projections to the cerebellum?

Answer 5

Important afferents arrive mainly from:
Spinal cord, from somatic proprioceptors and pressure receptors. Cerebral cortex (relayed via the pons).
Vestibular apparatus via the vestibular nuclei.
Enter via cerebellar peduncles and project to mainly to the granule cell layer

Question 6

From all three lobes of the cerebellum: the only output is via the axons of _____1_____ which mainly synapse on neurons of the _____2______ and subsequently contribute to coordinating the functions all of the motor tracts of the ________3__________

Most efferent axons of the deep cerebellar nuclei cross the midline and synapse in the _____4______. The thalamus in turn sends fibres to ______5_______.

Answer 6

1) Purkinje cells
2) deep cerebellar nuclei
3) brainstem and spinal cord (corticospinal, vestibulospinal, rubrospinal tracts).
4) thalamus
5) the motor cortex.

So output from purkinje cells once reaches the cerebellar nuclei can either go up to cortex and then down from a cortical tract or straight down a brain stem tract

Question 7

Cerebellar hemispheres influence the ______ side of the body

Answer 7

ipsilateral side
ie right controls right, left controls left
this is different from sensory and motor cortex

Question 8

Describe the effect of acute alcohol exposure on the cerebellum?

Answer 8

Acute alcohol exposure typically results in bilateral cerebellar hemisphere dysfunction and presents with cerebellar ataxia.

Results in slowed, slurred speech (dysarthria), bilateral incoordination of the arms and a staggering, wide based gait (cerebellar ataxia).

Question 9

What are the 3 functional divisions of the cerebellum?

Answer 9

Vestibulocerebellum
Spinocerebellum
Pontocerebellum

Question 10

What does the pontocerebellum do?

Answer 10

Receives information from the pons that originates in the cortex. The pontocerebellum functions in the planning and control of precise dexterous movements of the extremities, particularly in the arm, forearm, and hand, and especially in the timing of these movement.

Question 11

What does the spinocerebellum do?

Answer 11

Receives somatosensory input from the spinal cord; it uses this information to modify descending motor commands to facilitate movement, maintain balance, and control posture

Question 12

What does the vestibulocerebellum do?

Answer 12

The vestibulocerebellum regulates balance and eye movements. It receives vestibular input from both the semicircular canals and from the vestibular nuclei, and sends fibres back to the medial and lateral vestibular nuclei.

Question 13

3 functions of the basal ganglia?

Answer 13

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

Question 14

What is the basal ganglia?

Answer 14

A number of masses of grey matter located near the base of each cerebral hemisphere. (technically it is actually a nucleus because it’s a collection of nerve cell bodies in the CNS but the name ganglia has stuck).

Question 15

What are the five components of the basal ganglia?

Answer 15

Caudate nucleus
Putamen 
Globus pallidus 
Subthalamic nucleus 
Substantia nigra

Question 16

What 2 components of the basal ganglia are collectively known as the striatum?

Answer 16

Caudate nucleus
Putamen

(s for spiral, the caudate nucleus is kind of like a spiral and included in the striatum?)

Question 17

What 3 components of the basal ganglia are collectively known as the corpus striatum?

Answer 17

Caudate nucleus
Putamen
Globus pallidus

Question 18

What 2 components of the basal ganglia are collectively known as the lenticular nucleus?

Answer 18

Putamen
Globus pallidus

(they are the two bits on top of each other in the basal ganglia and it looks a little bit like a lentil)

Question 19

Describe what the internal capsule of the brain is?

Answer 19

The internal capsule is a white matter structure situated in the inferomedial part of each cerebral hemisphere of the brain. It carries information past the basal ganglia, separating the caudate nucleus and the thalamus from the putamen and the globus pallidus.

Question 20

What part of the brain is the substantia nigra found in?

Answer 20

The midbrain

Question 21

How does the substantia nigra get its name?

Answer 21

The cells literally stain themselves in life as they produce dopamine which has a by product which is black coloured that they can’t clear

Question 22

What type of cells are the output cells of the cerebellar cortex?

Answer 22

purkinje cells