1.8 Motor pathways

Question 1

hierarchy of motor movement control 3

Answer 1

Planning - Highest
Commanding
Execution

Question 2

components of planning in motor pathway hierarchy 3

Answer 2

cerebellum
basal ganglia
association areas

Question 3

components of commanding in motor pathway 2

Answer 3

primary motor cortex
descending pathways

Question 4

components of execution in motor pathway 2

Answer 4

motor neurons
interneurons

Question 5

two motor pathways + where do they decussate

Answer 5

lateral pathway - lateralcorticospinal tract = decussate at medulla

medial pathway = anteriocortical spinal tract decussate at spinal cord

Question 6

what are renshaw cells 3

Answer 6

inhibitory interneurons
activated by alpha LMNs
prevent overactivity of LMNs

Question 7

UMN, location and project from

Answer 7

cell bodies in primary motor cortex
project via internal capsule

Question 8

innervation ratio

Answer 8

the number of muscle fibres a motor neuron innervates

the smaller the ratio the finer the movement

Question 9

two types of LMNS

Answer 9

alpha LMN
gama LMN

Question 10

alpha motor neuron 3

Answer 10

innervates extrafusal fibres

supply whole muscle

function: muscle power

Question 11

gamma motor neuron 3

Answer 11

innervate intrafusal fibres

function: keep muscle spindles taut

Involved in stretch sensation

Question 12

first order neuron
second order neuron
third order neuron

Answer 12

First order neuron: UMN in primary motor cortex
Second order neuron: internuncial neuron in grey matter
third order neuron: LMN

Question 13

pathway of UMN to the spinal cord 8

Answer 13

primary motor cortex
premotor cortex
corona radiata
internal capsule
midbrain
ventral pons
basis pons
medulla - 85% decussate to form lateral corticospinal tract, 15% continue and decussate in the spinal cord to form the anterocortcial spinal tract

Question 14

lesion in premotor or supplementary areas results in, what is the clinical name

Answer 14

apraxia - difficulty in higher order planning, and execution

Question 15

UMN lesion 6

Answer 15

Spasticity
increased muscle tone - rigidity
no muscle atrophy
no fasiculations
hyperrefelexia
clonus
positive babinski sign

Question 16

LMN lesion 7

Answer 16

flacid
decreased tone
muscle atrophy
fasiculations
hyporeflexia
absent clonus
negative babinski sign

Question 17

postive vs negative babisnki sign

Answer 17

negative sign is when the toe curls downwards when pain stimuli applied along plantar surface = normal

positive babinski is when the curl goes upwards when pain stimuli applied along plantar surface. The reason for this hyperrefelexia