Motor Learning and Neurological Syndromes

Question 1

Which cortical area is involved with voluntary movement?

Answer 1

The Primary Motor Cortex

Question 2

Voluntary movement follows a monosynaptic pathway from

Answer 2

the cortex through an upper motor neuron, which synapses in anterior horn of the spinal cord

the lower motor neuron then synapses at the muscle

Question 3

Primary Motor Cortex: Which Broddmann area?

Answer 3

4

Question 4

Parasaggital Meningioma:

Answer 4

slow brain tumours, very little symptoms or notice symptoms because the tumour grows slowly

causes upper motor neuron symptoms due to pressure on the bones

Question 5

Upper Motor Neuron Disorders; Signs:

Answer 5

• weakness
• spasticity
• brisk reflexes
• babinski’s sign:
  - normal flexion
  - extension and flaring

upper motor neurons come from the cortex, through spinal cord

Question 6

Upper or lower motor neuron disease?

Answer 6

insert slide

upper motor neuron symptoms:
some flexor muscle movement
stronger extensors
increased tone
brisk reflexes

maintain posture due to spasticity

Question 7

Lower Motor Neuron Disease: Signs:

Answer 7

• weakness
• wasting of muscles
• fasciculations
• reduction in tone
• reduced reflexes

anterior horn cell to muscle cell

Question 8

Hierarchy of Control (3):

Answer 8

Strategy Level:
- goal of movement
- association areas of neocortex, basal
ganglia

Tactics Level:
- sequence of muscle contractions to
accurately achieve goal
- motor cortex, cerebellum

Execution Level:
- activation of motor and interneuron
pools to generate movement and
corrections
- brainstem, spinal cord

Question 9

How Do We Start Planning a Movement?

Higher Cortical Regions

Answer 9

• perceptual mechanisms generate a
  sensory representation of external
  world and individual
• posterior parietal cortex
• cognitive processes decide on course of
  action
• frontal lobes
• motor plan relayed to action systems to
  implement
• primary motor cortex

Question 10

Posterior Parietal Cortex: Brodmann Area:

Answer 10

• area 5
• area 7

Question 11

Premotor Area: Brodmann Number:

Answer 11

area 6

Question 12

Movement: Role of the Posterior Parietal Cortex:

Answer 12

• input from the spinothalamic
  tract/dorsal columns via the thalamus
• input from visual afferents
• localises body in space
• integrates sensory and visual
  information
• passes on information to the premotor
  area

Question 13

Movement: Posterior Parietal Cortex: Damage:

Answer 13

• damage leads to neglect
• problem with mental image
• able to perceive but not attend to
  information
• eg. drawing clock but all numbers are
  squashed on one side

Question 14

Movement: Role of the Premotor Area:

Answer 14

Lateral Premotor Cortex (PMC):
- input from the posterior parietal
cortex and cerebellum
- output via descending spinal tracts
- important in movements requiring
visual guidance

Medial Supplementary Motor Area:
- input from basal ganglia and the
posterior parietal complex
- output to the primary motor
cortex/spinal cord
- involved in co-ordinating more
complex voluntary movement

Question 15

Premotor Area:

Answer 15

Lateral Premotor Cortex (PMC):
- input from the posterior parietal
cortex and cerebellum
- output via descending spinal tracts
- important in movements requiring
visual guidance

Medial Supplementary Motor Area:
- input from basal ganglia and the
posterior parietal complex
- output to the primary motor
cortex/spinal cord
- involved in co-ordinating more
complex voluntary movement
- involved in the intention to move

Question 16

Apraxia:

Answer 16

• inability to carry out skilled movements
  in the absence of paralysis

Question 17

Ideational Apraxia:

Answer 17

unable to put together higher sequences to perform action eg show me how to brush your hair

Question 18

Ideomotor Apraxia:

Answer 18

unable to use tool
eg. show me show to use these scissors

Question 19

Utilisation Behaviour:

Answer 19

lesion in the prefrontal cortex/ supplementory motor area

Question 20

Motor Control of Movement:

Answer 20

motor regions feed in to basal ganglia and cerebellum
cerebellum into brainstem then spinal cord
then to sensory receptors

Question 21

Basagl Ganglia/Nuclei:

Answer 21

comprises of the striatum:
- caudate nucleu, putamen, nucleus
accumbens

comprises of the globus pallidus (external
and internal which extends to midbrain as a reticular part of substantia nigra)

subthalamic nucleus

pigmented compact part of substantia nigra

Question 22

Basal Ganglia: Movement:

Answer 22

• segregated into circuits to control
  movement
• circuits begin in the motor cortex
• cross basal ganglia
• return to cortex
• don’t initiate movement but involved in
  control

Question 23

Basal Ganglia: Motor Loops:

Answer 23

• direct pathway promotes activity
• indirect pathway promotes inhibition

Question 24

Both the direct and indirect pathways of basal ganglia motor loops receive excitatory cortical inputs which are ——ergic

Answer 24

glutamatergic

Question 25

Both the direct and indirect pathways of basal ganglia motor loops receive modulatory ------ergic input from the

Answer 25

- dopaminergic - substantia nigra

Question 26

Pathways within basal ganglia are ----ergic

Answer 26

GABAergic inhibitory

Question 27

Output from the basal ganglia and thalamus is tonically active but affected by

Answer 27

the direct and indirect motor loop pathways

Question 28

Basal Ganglia: Motor Loops: Direct Pathway:

Answer 28

- messages from the sensorimotor cortex stimulate the putamen and caudate nucleus - stimulates inhibitory neurons to the globus pallidus - the inhibitory neurons REDUCE inhibition to the thalamus - net result is increase in activity from the thalamus to the supplementary motor area and back to the motor cortex - results in promotion of activity

Question 29

Basal Ganglia: Motor Loops: Indirect Pathway:

Answer 29

- pathway activated by the supplementary cortex - message from putamen/caudate nucleus to globus pallidus externa is inhibitory - message then reduces inhibitory input to the subthalamic nucleus - this increase stimulation to the globus pallidus interna - increases the inhibitory signal to the thalamus therefore reducing the output to the supplementary motor area - promotes inactivity

Question 30

What is the main role of the motor loops of the basal ganglia?

Answer 30

to reinforce the chosen motor action to inhibit unwanted action

Question 31

Loss of inhibition from basal ganglia leads to

Answer 31

involuntary movements hyperkinetic disease eg: huntington's disease

Question 32

The cerebellum is connected to the brainstem by

Answer 32

the inferior and middle peduncles which are mainly afferents the superior peduncle which is mainly efferent

Question 33

All input into the cerebellum is excitatory or inhibitory?

Answer 33

excitatory

Question 34

Cerebellar: Efferents:

Answer 34

- efferents from the cerebellar cortex are from purkinje cells - inhibitory (GABA) - project to the cerebellar nuclei - efferents from cerebellar nuclei are excitatory

Question 35

Feedback pathway between the motor cortex and the cerebellum:

Answer 35

- afferents from the cerebral motor cortex synapse in the pons with afferents into the cerebellum - these afferents synapse with fibers in the dentate nucleus in the cerebellum and are excitatory - afferents to the cerebellar cortex also stimulate purkinje fibers which inhibit the dentate nucleus - dentate nucleus feeds back to the cerebral cortex via the thalamus - influences motor output from the primary motor cortex

Question 36

Pathway between the Vestibular Nuclei, Cerebellum and Spinal Cord:

Answer 36

- balance information from the vestibular apparatus sends afferents to the cerebellum - efferents from the fastigial nucleus synapse with the vestibulospinal tracts

Question 37

Relationship of Reticular Nuclei and Spinal Tractss:

Answer 37

- afferents from pontine and medullary reticular formations - efferents to spinal cord via reticulospinal tracts - facilitates the extension of limbs

Question 38

Tectospinal Pathway:

Answer 38

- originates in the superior colliculus in the midbrain - input from visual cortex - helps create a visual map to coordinate eye movements and head control descending pathway

Question 39

The rubrospinal pathway activates

Answer 39

flexor muscles in the arms

Question 40

Midline cerebellar lesions

Answer 40

affect trunk and axial muscles wide based gait seen (gait ataxia)

Question 41

Hemisphere cerebellar lesions cause

Answer 41

unilateral deficits function on same side as lesion nystagmus intention tremor