Vestibular pathways Flashcards
what are the two parts of the vestibulo spinal pathway
medial vestibular nucleus (MVN)
- head and neck
lateral vestibular nucleus (LVN)
- everything below neck
what is the MVN pathway in the vestibulo spinal pathway
- efferent neurons from MVN
- project down the ventral-medial portion fo the brainstem (medial longitudinal fasciculus)
- goes into cervical spinal cord to control neck muscles bilaterally (VCR)
what is the LVN pathway in the vestibulo spinal pathway
- efferent neurons from the LVN
- projects down the lateral vestibular tract to ventral horns in the thoracic, lumbar, and sacral spinal segments
- activates axial/proximal muscles controlling posture and balance
what is the vestibular cerebellar pathway
cerebellum receives inputs from the vestibular nucleus
also projects back to the vestibualr nucleus to influence vestibular spinal pathways
what are the roles of the cerebellum with vestibular reflexes
- adaptively fine tune VOR/VCR/VSR based on changes in sensory function
- involved in determining if vestibular signals are self generated vs external forces
why is it important to determine if vestibular signals are self generated or from external forces
need to be able to suppress the reflexes when we want
(ex: turn our head and our eyes follow = suppressed VOR)
is there a single vestibular cortex
no - info often integrated with other systems
- not a lot of vestibular info is processed separately
where is the parietoinsular vestibular cortex (PIVC)
close to S1
what is in the PIVC
neurons that integrate vestibular, visual optic flow, and somatosensory info
what does the PIVC do
provides a spatial frame of reference for proprioception and coordinating mvmt and posture
what are the 3a and 2v regions in the PIVC
3a = face / neck region of S1
2v = region just caudal to 3a
