Functional neuroanatomy of movement disorders

Question 1

features of UMN lesion

Answer 1

weakness, spasticity, clonus, and hyperreflexia, hypotonia

babies have low muscle tone

Question 2

what is a monosynaptic reflex

Answer 2

The monosynaptic stretch reflex, or sometimes also referred to as the muscle stretch reflex, deep tendon reflex, is a reflex arc that provides direct communication between sensory and motor neurons innervating the muscle.

Question 3

LCST decussation

Answer 3

medulla

fibres from motor cortex, motor area, premotor cortex, somatosensory cortex, parietal lobe and cingulate gyrus

Question 4

where is the primary motor cortex found

Answer 4

precentral gyrus of the frontal lobe

Question 5

what does the primary motor cortex do

Answer 5

Generates signals execute movement opposite side of body

Question 6

what does the secondary motor area include

Answer 6

posterior parietal cortex

premotor cortex ( anterior to primary MC)

supplementary motor area SMA above and medial to premotor area

Question 7

the secondary motor area includes is involved in motor planning
the posterior parietal Cortex is involved in the secondary motor area what does it do

Answer 7

• transforms visual info into motor commands eg steering hand to glass in space. It sends signals to premotor cortex and SMA

Question 8

what does the premotor cortex do

Answer 8

sensory guidance of movement controlling proximal and trunk muscles (orientation of body before reaching for the glass)

Question 9

what does the supplementary motor area SMA do

Answer 9

planning complex movements and coordinates two handed movements - tai chi, double handed tennis stroke

Question 10

the supplementary motor areas sequences of movement form memory. how does normal movement occur

Answer 10

start in premotor cortex and SMA goes

Question 11

BG receive input from …….. …….. …….. e.g. premotor cortex & supplementary motor areas (SMAs - sequences of movements from memory)
Integrates these signals & feeds back to pre-motor cortex via …………
Pre-motor cortex then activates the primary motor cortex (to execute movement) & the cerebellum (to coordinate & fine-tune the movement)
BG also have access to descending pathways for axial & proximal limb muscle control

Answer 11

BG receive input from cortical motor areas, e.g. premotor cortex & supplementary motor areas (SMAs - sequences of movements from memory)
Integrates these signals & feeds back to pre-motor cortex via thalamus
Pre-motor cortex then activates the primary motor cortex (to execute movement) & the cerebellum (to coordinate & fine-tune the movement)
BG also have access to descending pathways for axial & proximal limb muscle control

Question 12

wha is BSS

Answer 12

Brown-Sequard syndrome (BSS) is a rare neurological condition characterized by a lesion in the spinal cord which results in weakness or paralysis (hemiparaplegia) on one side of the body and a loss of sensation (hemianesthesia) on the opposite side.

Question 13

UMN
cortical grey matter - cell bodies
white matter tracts - myelin
spinal tracts

Answer 13

LMN 
ventral horn of spinal cord 
cauda equina 
peripheral nerve ( spinal and cranial) 
neuromuscular junction alpha * muscle fibres force) and gamma motor neurones ( innervate fibres in muscle spindles - measuring length and stretch of the muscle)

Question 14

UMN lesion

Answer 14

Paralysis of movement rather than individual muscles
Hypertonic muscles (spasticity) after a couple of days
‘Hopping rabbit’ posture
Moderate muscles wasting
Tendon reflexes increased & modified
Babinski sign
clonus

Question 15

LMN lesion

Answer 15

Paralysis of individual muscles
Hypotonic muscles (flaccidity)
Pronounced muscle wasting
Tendon reflexes absent

Question 16

what is the SMA

Answer 16

sequences of movements from memory – choreography like martial arts forms/kata, dance like Strictly (GABA)

BG & Cerebellum integrates these signals & feeds back to pre-motor cortex via thalamus

BG also have access to descending pathways for axial & proximal limb muscle control

Damage leads to spontaneous & inappropriate movement

Question 17

putamen and the caudate

Answer 17

striatus ( corpus striatum)

Question 18

putamen and the globus pallidus

Answer 18

lentiform nucleus

Question 19

caudate nucleus runs in the wall of what ventricle

Answer 19

lateral ventricle

Question 20

major role of the basal ganglia

Answer 20

imitation and termination of movement

neuronal activity in putamen seen before body movements
neuronal activity in caudate seen before eye movements

also involved in initiation and termination of some cognitive functions

Question 21

the basal ganglia is a collection of nuclear masses in the forebrain what is contained in the basal ganglia

Answer 21

caudate nucleus
putamen
globus pallidus

amygdala is anatomically and embryonically similar but functionally part of the limbic system

2 functionally related midbrain structures - substantia nigra and sub thalamus

Question 22

caudate nucleus it tadpole shaped - where is it found in comparison to the BG

Answer 22

most superior to BG
above and lateral to the thalamus and medial to internal capsule
enlarged head at the front which is continuous with the putamen

Question 23

what is the limbic system mad of

Answer 23

hippocampus, amygdala and hypothalamus

motivation dn mood

Question 24

what “loops does the limbic system have”

Answer 24

Motor loop
Oculomotor loop
Prefrontal loop – attention, planning, focus concentration
Limbic loop – emotional function – link between movement and emotion

Question 25

what is Korsakoff syndrome and what causes it

Answer 25

Korsakoff Syndrome. Korsakoff syndrome is a chronic memory disorder caused by severe deficiency of thiamine (vitamin B-1). Korsakoff syndrome is most commonly caused by alcohol misuse, but certain other conditions also can cause the syndrome.

high dose of thiamine

Question 26

substantia nigra does what

Answer 26

send dopaminergic neurones to basal nuclei

black substance due to melanin projecting to corpus striatum of BG - largest nucleus of the midbrain

Question 27

what is the subthalmus

Answer 27

The subthalamus is the most ventral part of the diencephalon.

Question 28

two problems causes by BG dysfunction

Answer 28

either hyperkinetic e.g. Parkinson’s - reduced or slow movement

hyperkinetic disorder - excessive abnormal spontaneous movement

Chorea
rapid, involuntary dancing movements eg Huntington’s disease
Ballismus
severe chorea with thrashing motions
Athetosis
Involuntary writhing (twisting & turning) movements of limbs & neck

Question 29

symptoms of Parkinsons

Answer 29

Tremor
Slow, pill-rolling
Asymmetrical
Worse at rest
Reduced on movement/distraction

Bradykinesia (slowness of movement)
Slow shuffling gate
Expressionless face with reduced blinking
Quiet monotonous speech
Micrographia (spidery writing)

Rigidity
lead-pipe rigidity in limbs, trunk & neck
cogwheel rigidity = rigidity + tremor

falls and dementia

Question 30

BG goes light what has happened

Answer 30

Degeneration of dopamine producing neurons (neuropigmented cells) in the pars compacta region of substantia nigra
- loss of melanin

Question 31

an example of a hyperkinetic disorder is Huntington’s disease - autosomal domino so 50%
caused by what

Answer 31

loss of GABA releasing neurone of the corpus striatum

chorea is primary feature
dementia, unsteadiness and speech problems
no effective treatment

Question 32

what is Wilsons disease

Answer 32

Wilson disease is a rare genetic disorder characterized by excess copper stored in various body tissues, particularly the liver, brain, and corneas of the eyes. The disease is progressive and, if left untreated, it may cause liver (hepatic) disease, central nervous system dysfunction, and death.

Researchers have determined that Wilson disease is caused by disruption or changes (mutations) of the ATP7B gene, which plays an important role in the movement of excess copper from the liver to the bile to eventually be excreted from the body through the intestines.

liver transplant

Question 33

what separates the cerebellum from the cerebrum

Answer 33

transverse fissure and tentorium cerebelli

median region separated from pons and medulla by 4th ventricle

Question 34

what does each cerebellar lobe do

Answer 34

Anterior lobe & posterior lobe = subconscious skeletal muscle movement
Flocculonodular lobe (inferior surface) = equilibrium & balance

Question 35

what is a cerebellar peduncle

Answer 35

A cerebellar peduncle is a nerve tract that permits communication between the cerebellum and the other parts of the central nervous system.

sup - efferent outpoin t
mid and inf afferent input from eyes , limbs etc

Question 36

sup cerebellar peduncles goes to where

Answer 36

midbrain

Question 37

mid c peduncles comes from voluntary motor signals from pons but where does inf c peduncles come from bringing vestibular apparatus of inner ear and body proprioceptors
and axons from medulla and spinocerebellar tracts of spinal cord to cerebellum

Answer 37

medulla

Question 38

DANISH

Answer 38

D ysdiadokokinesis
A taxia
Uncoordinated, staggering, broad-based gait 
Finger-nose ataxia (past-pointing)
Heel-knee-shin ataxia
Falls

N ystagmus
	(Involuntary, rapid, rhythmic eye   			movement)

I ntention tremor

S peech disturbance (dysarthria)

H ypotonia