Motor Disorders

Question 1

What are the parts of the basal ganglia ?

Answer 1

putamen + caudate = striatum
Globus pallidus
Sub thalamic nucleus
substantia nigra

Question 2

what side does the basal ganglia control and which tract does it use ?

Answer 2

contralateral side

Lateral corticospinal tract

Question 3

what chemical drives the motor cortex ? what receptors do they work on

Answer 3

dopamine
D1 receptors on
striatal neurones stimulating direct
D2 receptors inhibit the indirect

Question 4

what is the source of dopamine in the midbrain ?

Answer 4

Substantia nigra pars compacta

SNr

Question 5

what forms the lentiform nucleus ?

Answer 5

Putamen and Globus pallidus

Question 6

what communicates to the motor cortex via the basal ganglia and vice versa ?

Answer 6

the thalamus

Question 7

what is the functions of the basal ganglia ?

what about the pathways in the BG?

Answer 7

facilitate appropriate movements
Direct = excitatory (D1 receptors )
indirect = inhibitory

Question 8

what are the symptoms of Parkinson’s ?

Answer 8

Tremor, rigidity , bradykinesisa, mask face, depresion , dementia and hypophonia and explosive movements (hemiballismus), shuffling gait

Question 9

what is the main pathology of Parkinson’s ?

Answer 9

Caused by degeneration of dopaminergic neurones in SNc
Therefore have lost the dopamine-driven facilitation of
movement via both pathways

Question 10

what is Hunting’s chorea ?

Answer 10

Autosomal dominant, progressive disorder

Early onset around 30-50 years old

Question 11

what are the symptoms of Huntington’s ?

Answer 11

Chorea (dance-like movements due to increased motor
cortex activation)
• Dystonia (uncomfortable contractions of agonists and
antagonists simultaneously leading to odd postures
caused by over activity in agonist/antagonist muscle
circuits and loss of co-ordination between these)
• Loss of co-ordination
• Cognitive decline and behavioural disturbances (related
to role of basal ganglia in higher metal functions)

Question 12

what is the main pathology of Huntington’s ?

Answer 12

loss of inhibitory projections from

striatum to GPe - loss ofinibtory pathway. leading to loss on STN and over-activation = overactivation of thalamus

Question 13

What causes Hemiballismus ?

Answer 13

Can be caused by damage to subthalamic nucleus which
normally inhibits the thalamus via GPi
 Can be caused by sub-cortical stroke (lacunar infarct)
 Causes unilateral explosive (‘ballistic’) movements

Question 14

what is the main function of the cerebellum ?

Answer 14

to control sequence of movements

Question 15

What are the 3 parts the cerebellum and what are the functions?

Answer 15

Midline = vermis and controls the torso

2 lateral hemispheres = controls the ipsilateral sides

Question 16

How does the cerebellum communicate with the CNS?

Answer 16

via puduncles
superior cerebellar P –> midbrian
middle –> Pons
Inferior –> Medulla

Question 17

what is closely related to Cerebellum ?

Answer 17

4th ventricle . lesion in cerebellum can lead to hydrocephalus

Question 18

what sensory input is there on the cerebellum ?

Answer 18

ipsilateral spinal cord

contralateral sensory cortex

Question 19

what are the symptoms of Cerebellar disorders?

Answer 19

Dysdiadochokineasia/ Dysmetria  
Ataxic gait 
Nystagmus 
Intention Tremor
Slurred speech (dysartharia)
Hypotonia 
DANISH

Question 20

What side will symptoms show on cerebellar lesions ? why is that ?

Answer 20

ipsilateral -
Double cross due to outputs to the
contralateral motor cortex. Hence, ipsilateral signs of cerebellar
damage due to decussation of corticospinal pathway