L11: Central Control of Movement

Question 1

4 lobes of the cerebral cortex

Answer 1

1. Parietal (tactile sensations)
2. occipital (visual)
3. temporal (auditory, memory)
4. frontal lobe (motor processing, decision making , mood)

Question 2

UMNs start in the motor cortex & reach lower motor neurons via what two tracts

Answer 2

corticospinal or corticobulbar

Question 3

where do the corticobulbar pathways terminate

Answer 3

brain stem

Question 4

where do the corticospinal pathways terminate

Answer 4

spinal cord

Question 5

what cranial nerves are exclusively efferent motor pathways

Answer 5

III: oculomotor
XI: accessory
XII: hypoglossal

Question 6

what cranial nerves are mixed pathways (sensory and motor)

Answer 6

IV: Trochlear and VI: Abducens

Question 7

what cranial nerves are exclusively afferent sensory nerves

Answer 7

I: olfactory
II: optic nerves
VIII: vestibulochlear

Question 8

neurons of the corticobulbar tract arise from the ______ and synapse on the LMNs of the _______

Answer 8

lateral primary motor cortex
synapse on LMNs of the brainstem

Question 9

which CNs are LMNs

Answer 9

III-VII, IX-XII

Question 10

which cranial nerves are tested in the pupillary light reflex

Answer 10

II and III

Question 11

LMNs of the _______ tract run through the cranial nerves and determine motor control of the head and neck

Answer 11

Corticobulbar tract

Question 12

The corticospinal tracts arise from the ______ and synapse with LMNs in the ______

Answer 12

motor cortex
ventral horns
LMNs then exit the CNS

Question 13

UMNs decussate at the caudal end of the medulla near medullary structures called the ?

Answer 13

Pyramids (hence Pyramidal tract)

Question 14

LMNs from the _____ part of the ventral horn innervate muscles of the distal limbs

Answer 14

lateral

Question 15

LMNs from the _____ part of the ventral horn innervate muscles of the proximal limbs

Answer 15

ventral

Question 16

neurons of the extrapyramidal system are located where

Answer 16

nuclei of the brainstem
- red nucleus
- reticular formation
- vestibular nucleus
- tectum

Question 17

damage to any of the extrapyramidal tracts is associated with what

Answer 17

hypertonic and hypotonic pathology (depending on which tract is affected)

Question 18

condition caused by increased muscle tone and stretch reflexes, particularly the extensor muscles, resulting in extensor hypertonia

seen in hit by car accidents

Answer 18

Decerebrate rigidity

Question 19

what is opisthotonus

Answer 19

spasm of muscles causing backward arching of the head and neck

Question 20

the red nucleus forms the _______ tract

Answer 20

Rubrospinal

Question 21

the reticular formation forms the _____tract

Answer 21

reticulospinal

Question 22

the vestibular nucleus forms the _____tract

Answer 22

vestibulospinal

Question 23

the tectum forms the _____tract

Answer 23

tectospinal

Question 24

the rubrospinal tract sends input down the _____ white matter and the _____ part of the gray matter to the _____ musculature

Answer 24

lateral
lateral
distal

Question 25

the reticulospinal, tectospinal and vestibuospinal tracts all send input through the ____ white matter, and the ______ part of the gray matter to the _____ musculature

Answer 25

medial medial axial and proximal musculature

Question 26

the red nucleus receives input from the _______ and _______

Answer 26

motor cortex and cerebellum

Question 27

Rubrospinal tract neurons provide _____ to LMNs that control _____ muscles in the neck and proximal lumbs, buts inhibition to _______ muscles in the limbs

Answer 27

excitation flexor extensor

Question 28

is rubrospinal activation voluntary or involuntary

Answer 28

involuntary

Question 29

damage to the rubrospinal tract causes _________

Answer 29

extensor hypertonia

Question 30

Pontine reticulospinal tract neurons _____ alpha and gamma neurons to extensor muscles

Answer 30

excite

Question 31

medullar reticulospinal tract neurons _____ the pontine tract, therefore _____ extensor muscles

Answer 31

inhibit inhibiting

Question 32

lesions to the excitatory fibers of the reticular formation can result in ________ and this tends to occur in the ______ reticulospinal tract

Answer 32

hypotonia (flaccidity) Pontine

Question 33

lesions to the inhibitory fibers of the reticular formation can result in ________ and this tends to occur in the _____ reticulospinal tract

Answer 33

hypertonia (and spasticity) medullar tract

Question 34

the vestibular nuclues receives input from the vestibular appartarus of the _____ and ______

Answer 34

inner ear and cerebellum

Question 35

what tract contains sensory info on the position of the head

Answer 35

vestibulospinal

Question 36

what tract controls body position and disturbances in balance

Answer 36

vestibulospinal

Question 37

damage to the vestibulospinal tract causes ?

Answer 37

extensor hypotonia

Question 38

this allows for a balance in the descending influences onto extensor and flexor muscles AND alpha gamma coactivation

Answer 38

pontine tract neurons excite extensor muscles while medullar tract neurons inhibit the pontine tract to inhibit extensor muscles

Question 39

in the tectospinal tract, the superior (rostral) colliculus receives what input

Answer 39

visual, auditory and somatosensory input about environmental stimuli

Question 40

this tract is involved in reflex orientation of the head and eyes towards environmental stimuli and controls the axial and proximal musculature of the head

Answer 40

tectospinal tract

Question 41

Damage to this tract may cause disruption in the ability to orient the head towards and fix gaze on an object

Answer 41

tectospinal

Question 42

damage to ____neurons can cause an inability to move; hyperreflexia; increased muscle tone or muscle atrophy

Answer 42

UMNs

Question 43

Extrapyramidal tracts exert control on _____neurons to increase _____ control they can also interact with ____ nuclei and the ______ to fine tune motor control

Answer 43

Lower Motor Neurons Fine control Basal nuclei & the cerebellum

Question 44

cerebral palsy results in spasticity of skeletal muscles, this is an example of damage caused to _____neurons

Answer 44

Upper motor

Question 45

what three things are lower motor neurons innervated by

Answer 45

* Upper motor neurons * extrapyramidal neurons * reflex arcs

Question 46

what is the function of LMNs

Answer 46

stimulate muscles

Question 47

what can be caused from damage to LMNs?

Answer 47

* innapropriate or absence of movement (hyporeflexia, flaccid muscles, paraplegia) * muscle atrophy * reduced muscle tone

Question 48

what is muscle tone

Answer 48

the resting level of tension in a muscle as a result of alpha motor neurons

Question 49

reduced muscle tone results from damage of an _____motor neuron

Answer 49

alpha (LMN)

Question 50

increased muscle tone can result from damage to a ___neuron

Answer 50

upper motor neuron disturbs the balance of supraspinal inhibitory and excitatory inputs, producing a state of net disinhibition

Question 51

Decerebrate rigidity results from a ____ lesion

Answer 51

midbrain

Question 52

what is the major regulator of alpha motor neuron discharge

Answer 52

activity of muscle spindles

Question 53

explain alpha gamma coactivation

Answer 53

the gamma efferent sytem regulates the resting level of activity in spindle afferenta dn establishes a baseline level of alpha motor neuron activity in the absence of muscle stretch