Cerebellum

Question 1

Organization of the gray matter of the cerebellum

Answer 1

Molecular layer: next to pial surface, has few neurons
cell bodies of basket cells and stellate cells

Purkinje layer: contains the purkinje cell bodies (2nd superficial layer

Granular layer: deepest layer of gray matter
contains granule cells and a few golgi cells

White matter: axons of neurons

Question 2

Purkinje cell functions

Answer 2

Efferent cells

output crells from the cerebellar cortex

• inhibit the cerebellar nuclei and the vestibular nuclei
• neurotransmitter is GABA

Highly differentiated with many dendrites

Question 3

Granule cell functions

Answer 3

Only excitatiory neurons

• smallest neurons
• neurotransmitter is glutamate

Question 4

Stellate cell functions

Answer 4

axons synapse with only the purkinje cells and inhibit them
star shapped dendrites

found in the molecular layer

Question 5

Golgi cell function

Answer 5

inhibitory neurons
neurotransmitter is GABA

largely scattered neurons with short axons

Question 6

Basket cell function

Answer 6

their axons synapse with purkinje cells and nhibit them
found in the molecular layer

neurotransmitter is GABA

Question 7

What are the climbing fibers

Answer 7

Afferent fibers to the Cerebellum

• from the inferior olive
• Myelinated with excitatory influence on purkinje cells
• convey info regarding movement errors to the cerebellum

Question 8

What are the mossy fibers

Answer 8

from spinal cord, reticuar formation, vestibular system and pontine nuclei

• synapse with granulocytes
• convey somatosensory, arousal, equilibrium and cerebral cortex motor info to cerebellum

Question 9

Vestibulocerebellum

Answer 9

Division of the spinal cord that contains the nodulus and the flocculus

functional name for the flocculonodular lobe

• receives info directly from vestibular receptors
• sends output to the vestibular nuclei
• also recieves info from visual areas

Functions to influence eye movements and postural muscles of head and body

Question 10

Spinocerebellum

Answer 10

Functional name for vermis (medial) and paravermal (lateral) region

Somatosensory info, internal feedback from spinal interneurons and sensorimotor cortex

Functions to control ongoing movement via the brainstem descending tracts

• important for gait
• influences medial upper motor neurons and lateral upper motor neurons

Question 11

Pontocerebellum

Answer 11

Lateral hemispheres of cerebellum

input from cerebral cortex (premotor, sensorimotor, and others via the pontine nuclei
-functions in coordination of voluntary movements, planning of movements and timing

Question 12

Afferent fibers entering the cerebellum: Vestibular system

Answer 12

from the vestibular nuclei
Cranial nerve VIII

all via Mossy fibers

Question 13

Afferent fibers entering the cerebellum: Spinal cord

Answer 13

Anterior spinocerebellar tract (legs)
Posterior spinocerebellar tract (legs)
Cuneocerebellar tract (Arms)

all via mossy fibers
all enter through the Inferior Cerebellar peduncle

Question 14

Afferent fibers entering the cerebellum: Cerebral cortex

Answer 14

Cortico-pontinecerebellar (mossy)
Cortico- olivocerebellar (climbing fibers)
Cortico-reticulocerebellar (mossy)

all three enter the cerebellum through the Cerebellar peduncle

Question 15

nerve pathway of the Posterior cerebellar tract

Answer 15

Axons are carrying unconscious proprioception from lower limb

1st order neuron enters via the dorsal root ganglion and ascends in gracile fasciculus
-synapse in nucleus dorsalis of clark (C8-L2)

2nd order neuron will ascend in posterior spinocerebellar tract and enter the cerebellum via the inferior cerebellar peduncle (restiform body)

Question 16

nerve pathway of the cunecerebellar tract

Answer 16

Axons carrying unconscious proprioception from the upper limb

1st order neuron enters via the dorsal root ganglion and ascends in cuneate fasciculus
-synapses in accessory (external or lateral) cuneate nucleus

2nd order neuron form accessory cuneate nucleus ascends to cerebellum and enters via the inferior cerebellar nucleus (juxtarestiform body)

Question 17

nerve pathway of the anterior spinocerebellar tract

Answer 17

carries proprioception from the lower limb and will decussate at the level and travel in the anterior spinocerebellar tract

once it reaches the pons it will decusate again as it travels through the superior cerebellar peduncle to the cerebellum

Question 18

What travels through the superior cerebellar peduncle

Answer 18

major efferent route from the globose, emboliform, and dentate nuclei

afferent fibers from the ventral spinocerebellar tract run here aswell

Question 19

what travels through the middle cerebellar peduncle

Answer 19

largest peduncle

afferent fibers frompontine nuclei relayed to cortex

Question 20

what travels through the inferior cerebellar peduncle

Answer 20

Primarily afferent pathways from spinal cord

Question 21

what is the function of the vestibulocerebellum

Answer 21

eye movements
neck and trunk movements

flocculonodular lobe

Question 22

what is the function of the Spinocerebellum

Answer 22

Axial and lower extremity movements
gait and station

vermis and paravermal

Question 23

What is the function of the cerebrocerebellum

Answer 23

Percise, coordinated movements of extremities
Mainly upper extremity

lateral hemispheres of the cerebellum

Question 24

Information goes into the Dentate nucleus from where and goes to where

Answer 24

afferent is cerebrocerebellum and spinocerebellum via purkinje fibers

effernt will be to the Red nucleus and the ventral lateral thalamus

Question 25

Information goes into the globose and emboliform from where and goes to where

Answer 25

afferent: spinocerebellum and cerebrocerebellum efferent: red nucleus and thalamus (ventral lateral) these two nuclei can also be called the interposed nuclei

Question 26

Information goes into the fastigial nucleus from where and goes to where

Answer 26

Afferent: spinocerebellum, vestibulocerebellum efferent: Reticular formation and vestibular nucleus

Question 27

what is some information in the cerebellum that skips going to the deep nuclei of the cerebelllum

Answer 27

some afferents from the vestibulocerebellum will skip going to the deep nuclei and will travel on the purkinje fibers all the way to the vestibular nucleus

Question 28

What are the 4 deep nuclei of the Cerebellum

Answer 28

Fastigial, globose, emboliform, and the dentate

Question 29

how will cerebellar unilateral lesions affect the body

Answer 29

affects the ipsilateral side Ataxia: common to all lesions of cerebellum Voluntary normal strength, jerky and inaccurate movements not associated with hyperstiffness tend to fall to the side of the lesion

Question 30

Lesions to the vestibulocerebellumq

Answer 30

connections between the vestibular system and the flocculonodular lobe nystagmus Truncal ataxia: difficulty maintaining sitting and standing balance truncal instabillity -cant tandem walk

Question 31

Lesions of the spinocerebellum

Answer 31

connections between the cutaneous and proprioceptive information coming from the spinal cord to the vermis and paravermis regions gait and truncal ataxia: wide base, staggering base

Question 32

Midline ataxia

Answer 32

ataxic syndromes caused by vestibulocerebellar and spinocerebellar disease are called midline ataxia: Truncal instabillity -titubation: tremor of the trunk -gait ataxia: wide base, irregular steps with lateral veering Equilibratory (gait) ataxias -gait ataxia: wide based, irregular steps with lateral veering

Question 33

Lesions of the cerebrocerebellum

Answer 33

Dysarthria: slurred, poorly articulated speech Ataxic gait -staggering ataxic gait with tendency to fall toward side of the lesion Decomposition of movements Limb ataxia manifestations: Dysdiadochokinesia: inability to rapidly alternate movements Dysmetria: inability to accurately move an intended distance Action tremor: shaking of the limb during voluntary movement

Question 34

Cerebellar Ataxia

Answer 34

romberg test is positive unable to stand with feet together -with or without eyes open normal vibratory sense, proprioception and ankle reflexes

Question 35

Sensory Ataxia

Answer 35

Can stand with feet together with eyes open, but not closed (positive romberg test) abnormal vibratory sense, proprioception and ankle reflexes

Question 36

How to test for the vestibulocerebellum and spinocerebellum

Answer 36

station walking tandem gait

Question 37

How to test for the cerebrocerebellum

Answer 37

``` rapid alternating movements finger to nose toe to finger heel to shin rebound and check reflex speech ```