control of posture and locomotion Flashcards
1
Q
Lateral vistibulospinal tract
A
- Origin = lateral vestibular nucleus
- Descends to ALL spinal cord levels
- Function: facilitates alpha and gamma motor neurons of extensors muscles
- -> provides way for vestibular input to affect posture
2
Q
Medial vestibulospinal tract
A
- Origin = medial and inferior vestibular nucleus
- descends to upper thoracic cord
- FUNCTION: reflex head movements in response to vestibular stimuli
- -> adjust the position of the head in response to postural change
3
Q
Pontine reticulospinal tract
A
- ORIGIN = pontine reticular formation
- Descends to all levels of SC
- FUNCTION; adjustment of posture and body balance by facilitating alpha and gamma motoneurons to extensor muscles
4
Q
Medullary reticulospinal tract
A
- ORIGIN = medullary reticular formation
- FUNCTION: inhibit voluntary and cortically induced movement
- -> activation of this pathway DECREASES MUSCLE TONE
- -> inhibitory effect ons pinal reflexes and cortically induced movement (lesion to this tract leads to disinhibition contributing to spasticity)
5
Q
Reticulospinal system
A
- Function: modulate reflex action during movement
- -> integrates vestibular and other sensory input with motor commands from cerebral cortex
- -> role of making anticipatory postural adjustments to prepare for cortically controlled movements
- activating locomtion and controlling its speed
6
Q
tectospinal tract (colliculospinal tract)
A
- ORIGIN = superior colliculus
- projects to cervical spinal cord
- FUNCTION: important in coordinating head and eye movements
- -> can cause movement of the head in response to visual, auditory and somatic stimuli
7
Q
Sensory input for Vestibulocollic reflex
A
- Proprioceptive input fro neck muscle spindles and joint receptors in the NECK
8
Q
Sensory input for vestibulospinal reflex
A
- turning of head activates postural change in opposing side limb muscles
- ACTS ON THE LIMBS
9
Q
sensory input for cervicocollic reflex
A
- neck reflexes reacting on neck muscles contract stretched neck muslces: act synergistically with vestibulocollic reflexes
- Acts on the neck
10
Q
sensory input for Tonic neck reflexes
A
- In children AKA asymmetrical tonic neck reflex; head turned to one side, limbs on that side extend and other limbs flex; seen in adults when posture requires accurate control or upon vestibular damage
- acts on the neck and limbs
11
Q
describe asymmetrical tonic neck reflex
A
- AKA obligatory tonic neck reflexes
- seen in young infants
- head turned to one side, limbs on that side extend while opposite limbs flex
- almost identical to adult tonic neck reflex
12
Q
- Describe FEED-FORWARD mechanisms for controlling posture
A
- ANTICIPATE or PREDICT the effect of environmental distrubances (or mtoor command) wil have on variable to be controlled
- apply corrective action before there is error (postural adjustment
13
Q
describe feedback (aka compensatory) mechanisms for controlling posture
A
- Appropriate correct is applied AFTER ERROR id detected (loss of balance)
- automatic adjustments can be very rapid and improve with practice and learning
- Anticipatory mechanisms can sometimes predict postural disturbances and preprogram what stabilizing response will occur
14
Q
describe swinging room experiment in relationship to the role of vision in postural stability
A
- SWINGING ROOM EXPERIEMENT: when the room approaches, the subject sways back to avoid falling forward
- -> when the room moves away from the subject, the subject sways forward to avoid falling back
- toddlers can have difficulty standing with their eyes close and can fall easily during test since their posture is dependent upon vision
- adults just increase their body sway
15
Q
what sensory system involved in control of posture
A
- vestibular system = senses body sway through head motion
- Proprioceptive (muscle spindles, GTO, joint receptors)
- cutaneous receptors (touch and pressure)
- visual
