Spinal Cord & Motor Control

Question 1

Vertebral level and spinal cord level

Answer 1

C1-C2 V: C1-C2
C3-C7 V: C3-C8
T1-T2 V: T1-T2
T3-T10 V: T3-T12
T10-T12 V: L1-L5
L1 V: tip of spinal cord
Below L2 V: Cauda equina

Question 2

Ascending tracts pathways

Answer 2

DCML - posterior
ALS - posterior and lateral

Question 3

Descending tracts pathways

Answer 3

CCS - anterior and lateral

Question 4

Stretch reflex

Answer 4

Mono synaptic - test by hitting tendon of muscle (sensory input)

Question 5

Spinal reflexes

Answer 5

Requires a sensory stimulus!
Mono and polysynapatic

Question 6

Anterior Horn Cell

Answer 6

Is considered the final common pathway - multiple inputs

Question 7

Spinal cord lesion - at the level of the lesion

Answer 7

LMN signs:
Focal weakness, atrophy, decreased tone and absent reflexes

Question 8

Spinal cord lesion - Below the level of the lesion

Answer 8

UMN signs:
More diffuse weakness, atrophy only over time, increased tone and reflexes

Question 9

Physiology of Tone

Answer 9

Nonneural components: passive stiffness

Neural components: stretch reflex and descending influences from the AHC

Question 10

Hypertonia

Answer 10

abnormally increased resistance to passive lengthening of a muscle that is not attributed to pain

Spasticity or rigidity

Question 11

Decorticate vd decerebrate lesion location

Answer 11

Decerebrate - below red nucleus
Decorticate - above red nucleus

Question 12

Pathophysiology of spasticity

Answer 12

Increased input from sensory and descending drive after a lesion that results in an increased output to the spinal cord

imbalance of excitatory and inhibitory influences from reticule and vestibulospinal pathways

Question 13

When do monosynaptic reflexes return

Answer 13

1-4 weeks (initial hyperreflexia)

Question 14

When do polysynaptic reflexes return

Answer 14

1-2 days (initial reflex return)

Question 15

When will no reflexes be present

Answer 15

Spinal shock (24-72 hours)

Question 16

Requirements of bipedal locomotion

Answer 16

1. ability for reciprocal LE movement
2. Postural control
3. Initiation (of flexion and extension)
4. Adaptability

Question 17

Role of CPGs

Answer 17

Located within grey matter and are connected via commissural fibers

Pattern generators! Help with Reciprocal movement

Question 18

CPGs three major components

Answer 18

1. Rhythm generating network
2. Flexor-extensor alternation
3. Networks securing left-right alternation

NOT dependent on but its modulated by sensory input

Question 19

Propriospinal Interneurons and Networks

Answer 19

Communicate information over short and long distances in the spinal cord

Coordinate different parts of the body by linking motor circuits (arms swing with leg swing)

Connects CPGs! and allows for sensory input to modulate output

Question 20

What does the hip flexor stretch help

Answer 20

Helps facilitate the transition from stance phase to swing phase

Question 21

What does the supraspinal center help control

Answer 21

Initiation of walking via MLR
Adjustment to errors during walking
Visual guidance and obstacle avoidance via visual and motor cortex

Question 22

Role of basal ganglia in the supraspinal center

Answer 22

Action selection

Question 23

Role of MLR and reticulospinal neurons in the supraspinal center

Answer 23

Initiate locomotion

Question 24

Role of spinal CPGs and networks in the supraspinal center

Answer 24

Generate rhythm and pattern

Question 25

Role of muscle and skin in the supraspinal center

Answer 25

Modulates ongoing locomotor activity

Question 26

Role of cerebellar motor circuts in the supraspinal center

Answer 26

Adapt for external perturbations

Question 27

Role of motor and premotor cortex in the supraspinal center

Answer 27

Obstacle avoidance

Question 28

Examples of sensory stimuli to drive CPGs

Answer 28

Hip flexor stretch
Weight bearing
Visual cues
Perturbations for adaptations