Functional neuroanatomy of movement disorders

Question 1

Monosynaptic reflex arc

Answer 1

• Sensory neurone detects muscle spindle → cord in dorsal root ganglion
• Dorsal root ganglion enters ventral horn
• Synapses with motor neurone in ventral horn → spinal nerve → muscle of interest

Question 2

When you have a umn, what happens to your flexors and extensors?

Answer 2

Extensors are weaker, limbs in hyeprflexion

Question 3

Signs of UMN lesion

Answer 3

• Attenuated knee jerk
• Ankle jerk
• Ankle clonus - sustained beating of foot by stretching gastrocnemius
• Positive babinski

Question 4

Corticospinal tracts

Answer 4

Receive input from motor cortex -> internal capsule -> crus cerebri -> pons -> medulla -> tracts

Question 5

What is your pre-central gyrus?

Answer 5

Primary motor cortex

Question 6

How do the basal ganglia and cerebellum cooperate?

Answer 6

Basal ganglia starts movement, cerebellum makes it smooth

Question 7

Function of posterior parietal cortex

Answer 7

Transforms visual info into motor commands - sends signals to premotor cortex and SMA

Question 8

Function of premotor cortex

Answer 8

Sensory guidance of movement controlling proximal and trunk muscles

Question 9

UMN lesion sx

Answer 9

Paralysis of movement rather than individual muscles
Hypertonic muscles
Hopping rabbit posture
Babinski

Question 10

What happens when you have a LMN lesion?

Answer 10

Inhibits primitive reflex and causes massive response to stimulus - spasticity and exaggerated response

Question 11

LMN lesion sx

Answer 11

Paralysis of individual muscles
Flaccid muscles
Absent tendon reflexes

Question 12

Lentiform nucleus

Answer 12

Putamen + globus pallidus

Question 13

Basal ganglia function

Answer 13

Initiates and terminates movement
Neuronal activity in putamen seen before body movements
Neuronal activity in caudate seen before eye movements

Question 14

Function of limbic system

Answer 14

Fight/flight, smell, memory, reproductive behaviour and eating/feeding, emotion, survival, rewards

Question 15

Which two structures does the fornix connect?

Answer 15

Cingulate gyrus to hippocampus

Question 16

Wernicke’s encephalopathy

Answer 16

deficiency of vit B1 (thymin) - related to alcoholism - mammillary bodies shrivel up so break circuit of Papez so cam’t make memories - sx: amnesia, ataxia, confusion, opthalmoplegia

Question 17

Function of circuit of papez

Answer 17

Emotional expression

Hippocampus - thalamus - hypothalamus - mammillary bodies - cingulate gyrus - fornix - hippocampu

Question 18

Kluver-Bucy sundrome

Answer 18

Bilateral damage to amygdala

Question 19

Wilson’s disease

Answer 19

Copper accumulation and motor disorder

Question 20

3x peduncles in cerebellum

Answer 20

3x peduncle (top is efferent and bottom 2 are afferent)

Question 21

BG dysfunction symptoms

Answer 21

• Chorea: involuntary dancing movements e.g. Huntington’s disease
• Ballismus: severe chorea with thrashing motions
• Athetosis: writhing movements of limb and neck
• Movement disorder contralateral to affected side of BG

Question 22

Huntington’s

Answer 22

• Loss of GABA in corpus striatum
• Chorea
• Dementia, unsteadiness and speech problems

Question 23

Function of cerebellum

Answer 23

Learning new actions - timing and coordination

Question 24

DANISH

Answer 24

Dysdiadokokinesis 
Ataxia - uncoordinated, broad-based gait
Nystagmus 
Intention tremor
Speech disturbance
Hypotonia

Question 25

Symptoms of cranial nerve palsy

Answer 25

Nystagmus and dysarthria

Question 26

Symptoms of palsy in the arms

Answer 26

Finger-nose ataxia, intention tremor, dyasiakokinesis

Question 27

Symptoms of motor nerve palsy in legs

Answer 27

Heel-knee-shin ataxia, gait ataxia, falls

Question 28

Path of superior cerebellar peduncles

Answer 28

Run from cerebellum to midbrain

Question 29

Function of middle cerebellar peduncles

Answer 29

Voluntary motor signals from pontine nuclei to cerebellum

Question 30

Function of inferior cerebellar peduncles

Answer 30

Sensory info from vestibular apparatus of ear and body proprioceptors