DLA 23-24 and Lecture 21+22

Question 1

the embryo of the cerebellum

Answer 1

metencephalic protuberance

Question 2

general structure of cerebellum

Answer 2

right and left are divided by midline vermis

three lobes separated by two fissures

Question 3

lateral aspects of the cerebellum

Answer 3

mediate motor activity in the ipsilateral limbs

Question 4

medial aspects of the cerebellum

Answer 4

mediate motor activity of the trunk

Question 5

basal ganglia and motor activity

Answer 5

basal ganglia participates in the initiation and control of voluntary movement

receives + input from cerebral cortex

thalamus + input to cortex

basal ganglia - input to thalamus

Question 6

parts and role of substantia nigra

Answer 6

parts: 
pars reticulata (SNr) 
para compacta (SNc) 

dopamine released from the pars compacta regulates the function of the basal ganglia

Question 7

parts of the globus pallidus? (part of basal ganglia)

Answer 7

external lateral part (Gpe/GPL)

internal medial part (Gpi/GPM)

Gpi is the chief output nucleus

Question 8

Direct and indirect pathway with basal ganglia

Answer 8

direct:
disinhibits the thalamus resulting in the facilitation of movement

uses glutamate and GABA

indirect:
inhibits the thalamus which reduces movement

uses Glutamate and GABA

Question 9

Direct pathway process

Answer 9

cortex excites the striatum

striatal input inhibits Gpi

increase thalamic activity

Question 10

indirect pathway process

Answer 10

cortex excites the striatum

striatum inhibits GPe

inhibition of GPe = Sth to be active

Sth excites GPi

GPi excitation leads to inhibiting of the thalamus

less movement

Question 11

role of dopamine in direct and indirect pathway?

Answer 11

direct pathway:
D1R (excitation)

indirect:
D2R (inhibit)

Question 12

hypokinesis

Answer 12

slow movement

decreased inhibition of GPi
increased thalamic inhibition
decreased cortical activity
less dopamine released in PD

Question 13

clinical features of PD

Answer 13

decreased sense of smell
sleep disturbances
autonomic dysfunction

resting tremor
bradykinesia
rigidity
postural instability

Question 14

neuronal degeneration and HD

Answer 14

degeneration of GABAergic neurons that project to GPe

greater inhibition of Sth

reduced excitation of the GPi

reduced inhibition of thalamus

hyperkinesis = abnormal excessive movement

Question 15

Hemiballismus

Answer 15

violent flinging and rotary movements of limbs

arises from contralateral Sth injury

increased cortical excitation (reduced GPi)

one-sided hyperkinesia

Question 16

cerebellar dysfunction

Answer 16

regulates ipsilateral

acute cerebellar damage often yields motor deficits on the same side of the injury

Question 17

spino cerebellum (anterior lobe)

Answer 17

sensory feedback (trunk and limb movement)

Question 18

cerebro-cerebellum (posterior lobe)

Answer 18

integrating motor and sensory feedback

precise movements

Question 19

vestibulo-cerebellum (flocculonodular lobe)

Answer 19

afferents from vestibular apparatus

balance and eye movements

Question 20

middle and inferior cerebellar peduncle

Answer 20

afferent fibers

Question 21

superior cerebellar peduncle

Answer 21

efferent fibers

Question 22

Dorsal spinocerebellar spinal input

Answer 22

ascends ipsilaterally (lower limb)  
enters the cerebellum via inferior cerebellar peduncle 

from golgi tendon

Question 23

ventral spinocerebellar spinal input

Answer 23

arise from golgi tendon of lower limb (same side)

synapse at posterior horn

enter cerebellum via superior cerebellar peduncle

Question 24

cuneocerebellar spinal input

Answer 24

upper limb

enter inferior cerebellar peduncle

Question 25

lesions of spino-cerebellum (anterior lobe)

Answer 25

affect posture and movement of limbs

ataxias of the limbs usually same side (Ipsilateral)

gait ataxia

could be due to malnutrition

Question 26

cerebro-cerebellum (posterior lobe) lesion

Answer 26

affects accuracy and timing of movements

ataxia 
decomposition of movement 
dysarthria 
dyssynergia (uncoordination of limbs) 
intention tremor 
hypotonia

Question 27

Vestibulo-cerebellum lesion

Answer 27

Nystagmus (ocular ataxia)

tilted head
titubation (head nodding)
wide-based stance

Question 28

cerebellar tumor

Answer 28

usually astrocytoma or medulloblastoma (embryo)

rare in adults

symptoms of acute intracranial pressure

surgery and chemo is treatment

Question 29

motor signs of cerebellar tumor

Answer 29

Nystagmus
truncal ataxia
broad stance
hypotonia

Question 30

cerebellar stroke

Answer 30

potential arteries:

Posterior inferior cerebellar arteries (PICAs)
Anterior inferior cerebellar arteries (AICAs)
Superior cerebellar arteries (SCA)

motor signs:
dysarthria
truncal ataxia

ipsilateral motor signs: 
dyssynergia 
intention tremor 
limb ataxia 
rebound phenomenon 

edema in posterior fossa

Question 31

malnutrition and the cerebellum

Answer 31

B1 deficiency is linked to the degeneration of the rostral vermis and adjacent parts of the anterior cerebellar lobe

cortical purkinje fibers degenerate

motor signs involve legs and trunk

Question 32

Louis-Bar syndrome (Ataxia telangiectasia)

Answer 32

autosomal recessive disorder with multiorgan development

neurologic: 
cerebellar dysfunction 
degeneration of the purkinje fibers 
enlarged brain areas (4th ventricle) 
impaired motor skills 

skin and eyes will show small dilated blood vessels

increased vulnerability to radiation and cancer development