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Control eye movements and gaze stabilization, maintain posture/equilibrium (postural adjustments)
Motor purpose in vestibular system
- 4 nuclei
- 6 pathways
- vestibulocerebellum
- vestibular cortex
Central vestibular system
The cerebellum controls which reflex that is related to the vestibular system?
Vestibulo-ocular reflex
output:
Nausea and vomiting, altered consciousness
reticular formation
output:
posture of head and body
Cerebral cortex ; SC ; reticular formation
- Vestibulo-ocular reflex
- Motor impulses to control eye movements
- Motor impulses to make postural adjustments
Motor input relating to vestibular system
Perception of motion and orientation
Sensory purpose of vestibular system
- Vestibular information
- Vision
- Proprioception
- Tactile information
- Auditory information
Sensations relating to the vestibular system
output:
eye movements
extraocular nuclei
- Vestibular nuclei (brainstem)
- Cerebellar pathways
CNS components of vestibular system
Postural, motor and oculomotor control
Purpose of vestibular system
Motor impulses to control eye movements and motor impulses to make postural adjustments are controlled by which brain structure?
Brainstem
- The cerebellum coordinates and regulates posture, movement, and balance
- The cerebral cortex contributes higher level thinking and memory
- The brainstem integrates and sorts sensory information
Integration of input from the CNS
- Vestibule (sensory organ)
- CN 8 (vestibulocochlear)
PNS components of vestibular system
output:
head movement
superior colliculus; accessory nerve
Vestibular: equilibrium, spatial awareness, rotation, linear movement
Visual: sight
Proprioceptive: touch
Sensory input of vestibular system
Central processing comes from ...
The thalamus
output:
Conscious awareness of head position and movement
Vestibular cortex
T/F: Reflexes combine both systems to create involuntary reactions
True
- Vestibulo-ocular (VOR)
- Vestivulospinal (VSR)
- Vestibulocolic (VCR)
Reflexes of the vestibular system
System of fluid filled tubes and sacs, which runs functions such as hearing and balance
Labyrinth
- Stabilizes gaze during head motion
- Fastest reflex in the body
- Compensatory eye movements are generated
- EX: rotation of head to left results in rightward compensatory eye movement
Vestibulo-ocular reflex (VOR)
- Stabilizes head in space by activating neck musculature
- Neck muscle activation to stabilize head in space, compensates for head displacement during gait
Vestibulocolic reflex (VCR)
- Maintains vertical alignment of trunk
- When head tips in one direction, the body elongates to that side and shortens on the other
Vestibulospinal reflex (VSR)
Hearing
- Cochlea (transmits sound to brain)
Balance
- Vestibular organs (head movements)
- Semicircular canals
- Otoliths
Labyrinth function