Chapter 14

Question 1

Upper motor neurons are classified as…

Answer 1

Postural/gross movement tracts
Selective motor control tracts
Nonspecific tracts

Question 2

Postural/gross movement tracts

Answer 2

Control contraction of antigravity muscles and groups of limb muscles

Question 3

Selective motor control tracts

Answer 3

Isolates contraction of individual muscles of the limbs and face
Ex. Extending index finger while other fingers remain flexed

Question 4

Nonspecific motor tracts

Answer 4

Facilitate all lower motor neurons
Contribute to background levels of excitation in the cord and facilitate local reflex arcs

Question 5

Medial motor tracts

Answer 5

Synapse with lower motor neurons that innervate postural and limb muscles

Question 6

Lateral corticospinal tract

Answer 6

Only tract that facilitates specific lower motor neurons innervating the distal muscles, wrist and finger extensors, ankle and toe dorsiflexors, and hand and foot intrinsic muscles
Most important pathway controlling voluntary movement

Question 7

Reticulospinal, medial/lateral vestibulospinal, and medial corticospinal tracts

Answer 7

Deliver signals that control posture and gross limb movements to medial lower motor neuron pools in the spinal cord

Question 8

Reticulospinal tract

Answer 8

Neurons activate LMNs that elicit simultaneous contraction of muscle groups across multiple joints
Provides anticipatory postural adjustments, prepare body for upcoming movement
Controls basic synergies: flexor or extensor synergies of the limbs
Essential for coordinating muscular activity of the trunk and the proximal muscles of all 4 limbs during walking
Elicits voluntary gross reaching and grasping movements

Question 9

Muscle synergy

Answer 9

The activation of a group of muscles to achieve a specific task
Normal synergies simplify movements: ex. Neck reflexes, coordination during walking, reaching and grasping

Question 10

Medial vestibulospinal tract

Answer 10

Receive information about head movement and position from the vestibular apparatus located in inner ear
Originals in vestibular nucleus ad projects bilaterally to the cervical and thoracic spinal cord

Question 11

Lateral vestibulospinal tract

Answer 11

Respond to gravity information from vestibular apparatus
Facilitates ipsilateral LMNs to extensors while inhibiting ipsilateral LMNs to flexors

Question 12

Medial corticospinal tract

Answer 12

Descends from the cortex through the internal capsule and the anterior brainstem
Synapse with LMNs that control neck, shoulder, and trunk muscles
Provide voluntary muscle control

Question 13

Selective motor control

Answer 13

Ability to activate individual muscle independently of other muscles
Essential for normal movement of the hands

Question 14

Rubrospinal tract

Answer 14

Arises in the red nucleus of the midbrain

Question 15

Raphespinal tract

Answer 15

Releases serotonin, modulating the activity of spinal LMNs
Activated during intense emotions
May contribute to poorer motor performance when anxiety is high

Question 16

Ceruleospinal tract

Answer 16

Releases norepinephrine, producing tonic facilitation of spinal LMNs
Activated during intense emotions
May contribute to poorer motor performance when anxiety is high

Question 17

Corticobrainstem tracts

Answer 17

Provide voluntary control of muscles in the head and many muscles in the neck
Facilitates LMNs innervating the muscles of the face, tongue, pharynx, and larynx, and the trapezius and sternocleidomastoid muscles

Question 18

2 regions anterior to the primary motor cortex are involved in preparing for movement

Answer 18

Premotor area on the lateral surface of the hemisphere
Supplementary motor area on the superior and medial surface

Question 19

UMN syndrome

Answer 19

Arises from UMN lesions
Causes: stroke, SCI, TBI, abnormal development, neurodegenerative disorders, anoxic brain injury, tumors, infections, inflammatory disorders, and metabolic disorders

Question 20

Stroke

Answer 20

Sudden onset of neurological deficits due to disruption of the blood supply in the brain
Affects middle cerebral artery damaging corticospinal, corticoreticular, and Corticobrainstem tracts

Question 21

Complete spinal cord injury

Answer 21

Severs all ascending and descending axons
Total absence of sensory and voluntary motor function below injury

Question 22

Incomplete spinal cord injury

Answer 22

Some axons are spared and the spinal cord below the lesion is able to convey some messages
Interferes with selective motor control doing overground walking

Question 23

In spastic CP

Answer 23

All of the motor deficits arise from damage to corticospinal, corticoreticular, and corticobrainstem tracts during perinatal period
Has both spinal and cerebral lesions

Question 24

ALS

Answer 24

Causes death of both upper and lower motor neurons

Question 25

Signs of UMN syndrome

Answer 25

Variety of neuralgic signs and abnormal muscle tone that are categorized as loss of function and gain of function

Question 26

Loss of function

Answer 26

Absence of a feature that is normally present
Ex. Paresis/paralysis, absent/decreased muscle tone, impaired selective motor control

Question 27

Gain of function

Answer 27

Presence of a feature that is not normally present
Ex. Spasticity, rigidity, abnormal reflexes, compensatory cocontraction

Question 28

Muscle tone

Answer 28

Resistance to stretch in resting muscle

Question 29

Abnormal resistance from loss of function

Answer 29

Flaccid, hypotonia

Question 30

Normal resistance to gain of function

Answer 30

Spasticity, dependent hypertonia

Question 31

Hemiplegia

Answer 31

Weakness affecting one side of the body

Question 32

Paraplegia

Answer 32

Affects the body below the arms

Question 33

Tetraplegia

Answer 33

Affects all 4 limbs

Question 34

Lateral corticospinal tract lesions

Answer 34

Prevent normal coordination throughout the limbs

Question 35

Hyperreflexia

Answer 35

Excessive reflex response to muscle stretch
Caused by reduced descending inhibition of LMNs and the subsequent development of interneuron and LMN excessive excitability
Contributes to movement disorders post spinal cord injury and in spastic CP