Exam 2: The Cerebellum

Question 1

Size of Cerebellum

Answer 1

• Huge, even in humans
  ii. Contains 3.6 times more neurons than neocortex
  ii. Contains more neurons then the rest of the brain combined

Question 2

Functions of Cerebellum

Answer 2

a. The cerebellum receives massive sensory inputs, which help it ensure smooth ongoing motor movements
b. The cerebellum does not directly synapse onto lower motor neurons, but instead sends axons to the brainstem and motor areas of the cortex to exert its influence
c. The cerebellum also participates in articulation of speech, motor learning and possibly some higher cortical functions

Question 3

The cerebellum and the cerebral cortex share many features:

Answer 3

1) Grooved structure
2) A deep fissure divides the structure into two lobes
3) Outer portion contains layers of neuronal cell bodies while the inside is mainly axons
4) Subcortical nuclei (aka cell bodies) are present
5) Input from sensory systems and output motor commands

Question 4

What do the cerebellar peduncles do?

Answer 4

The cerebellum is attached to the pons and medulla by three axonal tracts that leave/enter the cerebellum from the brainstem, called the cerebellar peduncles

Question 5

What is the vermis and what does it control?

Answer 5

The midline of the cerebellum is called the vermis; proximal and trunk muscle control (medial anterolateral corticospinal tract

Question 6

What are the lobes of the cerebellum and how are they separated?

Answer 6

The lobes of the cerebellum are the anterior lobe and the posterior lobe, which are separated by the primary fissure

Question 7

WHat is the posterolateral fissure?

Answer 7

the posterolateral fissure separates the posterior lobe from the flocculonodular lobe

Question 8

What is the floccolonodular lobe and what does it control?

Answer 8

is important for connections to the vestibular nuclei; vestibuloocular control

Question 9

What is significant about the cerebellar tonsils?

Answer 9

the cerebellar tonsils can herniate through the foramen magnum when there is increased intracranial pressure, which then causes pressure on the medulla and can lead to death due to impinegement on medullary respiratory center

Question 10

Superior peduncle

Answer 10

outputs from the cerebellum to brainstem

Question 11

Middle peduncle and Inferior peduncle

Answer 11

inputs to the cerebellum

Question 12

What does the intermediate part of the cerebellum control?

Answer 12

control of distal muscles in the arms and legs

Question 13

What does the lateral part of the cerebellum control?

Answer 13

– planning and motor program for the extremities (limbs)

Question 14

What do the deep nuclei of the cerebellum do?

Answer 14

1) The deep nuclei are the output of the cerebellum, every axons that leaves the cerebellum does so from cell bodies in the deep nuclei
a. So the overall circuitry is cells in the “outer” aspects of the cerebellum send axons to the deep nuclei and then the axons from the deep nuclei leave the cerebellum

Question 15

Denate nucleus

Answer 15

receive inputs from lateral cerebellar hemispheres and are active just before voluntary movements are made

Question 16

Emboliform

Answer 16

receive inputs from the medial cerebellar hemispheres and are active during the duration of a movement

Question 17

Glubose

Answer 17

receive inputs from the medial cerebellar hemispheres and are active during the duration of a movement

Question 18

Fastigial

Answer 18

receives input from the vermis and the flocculonodular lobes