CNS Part 3

Question 1

While the Corticospinal (Anterior & Lateral) and Corticobulbar
Pathways regulate the activity of the LMN, there are other descending
motor pathways that originate in the brainstem that regulate the —,
too.

Answer 1

LMN

Question 2

The UMN from each of
these tracts synapse with
the LMN in the

Answer 2

ventral gray

horn (*) of the spinal cord

Question 3

indirect tract: rubrospinal
location of UMN:
site of cross over:
function:

Answer 3

location of UMN: red nucleus in midbrain
site of cross over: midbrain
function: upper limb muscle tone and movement

Question 4

indirect tract: tectospinal
location of UMN:
site of cross over:
function:

Answer 4

location of UMN: midbrain (superior and inferior colliculi)
site of cross over: midbrain
function: regulation of eye head, neck, and UL position in response to visual and auditory stimuli

Question 5

indirect tract: vestibulospinal
location of UMN:
site of cross over:
function:

Answer 5

location of UMN: vestibular nucleus (pons and medulla)
site of cross over: none, control ipsilateral muscles
function: regulation of balance and muscle tone

Question 6

indirect tract: reticulospinal
location of UMN:
site of cross over:
function:

Answer 6

location of UMN: medial RS (pons +) lateral RS (medulla -)
site of cross over: none, controls ipsilateral muscles
function: regulates muscles of the trunk and limbs maintaining posture and tone in response to ongoing body movements

Question 7

The red nucleus in the
midbrain/mesencephalon receives fibers from
the

Answer 7

primary motor cortex (corticorubral tract)

Question 8

The red nucleus give rise to the
— —, which crosses to
the opposite side of the brainstem and travels
alongside the corticospinal tract into the
lateral columns of the spinal cord

Answer 8

RUBROSPINAL TRACT

Question 9

Rubrospinal Pathway functions as an

Answer 9

accessory route for 
transmission of signals from the primary 
motor cortex to the spinal cord. Fibers 
terminate on interneurons and motor 
neurons of the spinal cord involved in 
upper limb muscle tone and movement.

Question 10

The TECTOSPINAL Tract arises

from the

Answer 10

superior and inferior colliculi

midbrain

Question 11

the tectospinal pathway regulates the (4)

Answer 11

eye, head, neck and upper limb position in response to visual (superior
colliculus) or auditory (inferior colliculus) stimuli.

Question 12

The Vestibular Nuclei (in Pons and 
Medulla Oblongata) transmit excitatory 
signals through the --- --- to control antigravity muscles 
(proximal limb extensors and head/neck 
muscles) to maintain balance and muscle 
tone.

Answer 12

VESTIBULOSPINAL

Tracts

Question 13

Vestibulospinal Pathway controls

Answer 13

muscles on the same side of the

body (these fibers to not decussate)

Question 14

Reticulospinal Pathway
Medial -
Lateral -

Answer 14

Pontine

Medullary

Question 15

Pontine RS pathway activates

Answer 15

axial muscle of the body
(muscles of the vertebral column and extensors of the
limbs). Have a high degree of background activity.
Regulated by the Vestibular nuclei, cerebellar nuclei
and cerebral cortex.

Question 16

Medullary RS pathway is an

Answer 16

antagonist to the activity of
the Pontine RS Pathway. The medullary reticular nuclei
receive strong input from the corticospinal tract and
rubrospinal tract.

Question 17

Reticulospinal Pathway controls muscles on the

Answer 17

same side of the body (these fibers to not decussate)

Question 18

UMN Activity is Regulated by the — — via

the Thalamus

Answer 18

Basal Nuclei

Question 19

The Basal Nuclei are involved in

Answer 19

initiating and terminating movements,
suppressing unwanted movements and
establishing a normal level of muscle
tone

Question 20

Parkinson’s Disease

Answer 20

A Hypokinetic Disorder
• Loss of Dopaminergic neurons from 
the Substantia Nigra that project to 
the Striatum, where they inhibit 
Cholinergic neurons. 
• Clinical Manifestations:  Bradykinesia, 
Cogwheel Rigidity, Pill Rolling, 
Tremor, Shuffling Gate, Stooped 
Posture, Depression, Dementia

Question 21

Tremor can impact the tongue and lips

impacting

Answer 21

mastication, swallowing and speech.

Question 22

Most common oral manifestations due to the

medications (targeted at dopamine) include

Answer 22

difficulty with oral hygiene, xerostomia, burning
mouth/mucositis, difficulty swallowing, drooling
and less caries/more teeth than age-matched
controls.

Question 23

Huntington Disease

Answer 23

A Hyperkinetic Disorder
• Autosomal Dominant Genetic 
Disease
• Loss of GABAergic neurons, 
resulting in reduced inhibitory 
output from the Striatum. 
• Clinical Manifestations: Chorea 
(multiple, rapid, random 
movements), athetosis (slow 
writhing movements), personality 
changes, dementia

Question 24

Grimacing, speech difficulties and
dysphagia can occur. Treatment can be
hindered by

Answer 24

involuntary mouth and jaw
movements. Sedation may be required for
treatment of some patients.

Question 25

UMN Activity is Regulated by the — via

the Thalamus

Answer 25

Cerebellum

Question 26

The Cerebellum is involved in

Answer 26

monitoring differences
between intended movements and movements actually
performed. It issues commands to UMN to reduce errors
in movements. It also coordinates body movements to
maintain normal posture and balance.

Question 27

functional zone: spinocerebellum
location in cerebellum:
receives input from:
function:
effect of lesions:

Answer 27

location in cerebellum: vermis (trunk and proximal limbs) and intermediate zones (distal limbs)
receives input from: muscle spindles and GTOs via spinocerebellar tracts
function: coordination of body and limb movement; maintenance of muscle tone
effect of lesions: ataxia dysmetria intention tremor hypodontia

Question 28

functional zone: vestiulocerebellum 
location in cerebellum:
receives input from:
function:
effect of lesions:

Answer 28

location in cerebellum: flocculonodular lobe
receives input from: vestibular nuclei CN VIII, superior colliculi, and visual cortex
function: balance and eye movements
effect of lesions: vertigo, nystagmus

Question 29

functional zone: cerebrocerebellum 
location in cerebellum:
receives input from:
function:
effect of lesions:

Answer 29

location in cerebellum: lateral zones
receives input from: cerebral cortex and inferior olivary nucleus in medulla
function: planning and execution of movement; coordinating complex sequential movements
effect of lesions: abnormal coordination of ipsilateral movements, dysdiadochokinesia, dysmeria, intention tremor

Question 30

Cerebellar diseases result in (3)

Answer 30

alterations
in gait, balance and coordination of
motor activities; not paralysis

Question 31

functional zone: spinocerebellum
location in cerebellum:
function:

Answer 31

location in cerebellum: vermis (trunk and proximal limbs) and intermediate zones (distal limbs)
function: coordination of body and limb movement; maintenance of muscle tone

Question 32

functional zone: vestibulocerebellum
location in cerebellum:
function:

Answer 32

location in cerebellum: flocculonodular lobe

function: balance and eye movements

Question 33

functional zone: cerebrocerebellum
location in cerebellum:
function:

Answer 33

location in cerebellum: lateral zones

function: planning and execution of movements; coordinating complex sequential movements

Question 34

Lesions of 
the medial part of 
cerebellum 
(vermis, flocculonodular 
lobe, and corresponding 
deep nuclei) 
affect

Answer 34

medial structures 
(i.e., axial 
and proximal limb 
musculature), resulting 
in symptoms 
including trunk ataxia 
and nystagmus.

Question 35

Lesions of the lateral parts
of cerebellum (lateral
zones)
affect

Answer 35

lateral structures 
(distal limb musculature), 
resulting in symptoms 
such as ipsilateral limb 
ataxia.

Question 36

The vestibulocerebellum is not shown in this diagram. It receives input from the

Answer 36

vestibular system and it adjusts the action of the Reticulospinal and vestibulospinal pathways.

Question 37

The tectospinal tract is not shown here, but it rises from the

Answer 37

superior colliculus (midbrain) and it causes head turning in response to sudden visual or auditory stimuli.