Neurophys posture and locomotion

Question 1

What is the origin and destination of the lateral vestibulospinal tract?

Answer 1

Originates within the lateral vestibular nucleus and travels through all levels of cord.

Question 2

What is the origin and destination of the medial vestibulospinal tract?

Answer 2

Medial and inferior vestibular nucleus.

Descends into upper thoracic cord.

Question 3

What is the origin and destination of the pontine reticulospinal tract?

Answer 3

Originates in the pontine reticular formation and descends to all levels of the spinal cord.

Question 4

What is the origin and destination of the medullary reticulospinal tract?

Answer 4

Medullary reticular formation

Destination not stated.

Question 5

What is the origin and destination of the tectospinal tract?

Answer 5

Originates in the superior colliculus and projects only to the cervical spinal cord.

Question 6

What is the function of the lateral vestibulospinal tracts?

Answer 6

Alpha and gamma motor neurons to the extensor muscles allowing the vestibular system to affect posture.

Question 7

What is the function of the medial vestibulospinal tract?

Answer 7

Reflexes in head movements from vestibular stimuli and postural changes.

Question 8

What is the function of the pontine reticulospinal tract?

Answer 8

Adjustment of posture and body balance by facilitating alpha and gamma motorneurons to extensor muscles.

Question 9

What is the function of the medullary reticulospinal tract?

Answer 9

Inhibits voluntary cortically induced movement.

Decreases muscle tone

Inhibits spinal reflexes and cortically induced movement.

Question 10

What is the function of the reticulospinal system?

Answer 10

Modulates reflex action during movement.

Integrates vestibular and other sensory input with motor commands from cerebral cortex*****

Maks anticipatory postural adjustments.

Activates locomotion and controls its sped.

Question 11

What is the function of the tectospinal tract?

Answer 11

Coordinates head and eye movements in response to visual, auditory, or somatic stimuli.

Question 12

What is the sensory input to the vestibulocollic reflex and where does it act?

Answer 12

Proprioceptive input from neck muscle spindles and joint receptors acting on the neck.

Question 13

What is the sensory input to the vestibulospinal reflex and where does it act?

Answer 13

Turning of the head activates postural change in opposing side limb muscles.

Question 14

What is the sensory input to the cervicocollic reflex and where does it act?

Answer 14

Neck reflexes reacting on neck muscles causing contraction of stretched neck muscles.
Acts synergistically with vestibulocolic reflexes.

Question 15

What is the sensory input to the aymetrical tonic neck reflexes and where do they act?

Answer 15

Asymetrical tonic neck reflex.
when head turned to one side limbs on that side extend and others flex.
“Fencers pose”

Question 16

Where are the pattern generators found that control flexion and extension during locomotion?

Answer 16

Found within the spinal cord.

Question 17

What is Decrebate posturing?

What lesion will cause this condition?

Answer 17

Extension of all four limbs and neck.

Seen in lesions of the upper pons.

Question 18

What is responsible for the extension seen in Decrebate posturing following a lesion?

Answer 18

If the lesion is below the red nucleus but above vestibular nuclei. Lateral vestibulospinal tracts try to increase extensor motor neurons to compensate for lesion. Leads to extension of all limbs.

Question 19

What is decorticate posturing?

What lesion will cause this?

Answer 19

Arms are fexed and legs are extended when patient is on back and head forward.

From lesions to the internal capsule.

Question 20

What tracts specifically cause decorticate lesions?

Answer 20

Loss of control of the vestibulospinal and tonic neck reflexes from cortical control cause flexed arms and extended legs.

Question 21

What happens if you turn the head of a patient exibiting decorticate posturing?

Answer 21

Obligatory neck relfexes.

Limbs on side of head extend and opposite flex.