Vestibular pathways Flashcards
How is the head controlled by the vestibular system?
Desending projections from the vestibular nuclei are mediated by the vestibulo-cervical reflex.
This involves the medial vestibular nuclei. Axons from the nucleus descend in the medial longitudinal fasciculus to reach the upper cervical levels of the spinal cord.
This pathway regulates head position by reflex activity of neck muscles in response to stimulation of semi-circular canals caused by rotational accelerations of the head.
How is the body controlled by the vestibular system?
The vestibulo-spinal reflex is mediated by both the lateral and medial vestibular spina tracts and reticulo spinal tracts.
Inputs from the otolith organs project mainly to the lateral vesicular nucleus , which sends axons in the lateral vestibulo-spinal tract to the spinal cord.
These axons terminate monosynaptically on extensor motor neurons and disynaptically inhibit flexor motor neurons. The result is a powerful excitatory influence on the extensor muscles.
What projections are sent from the vestibular pathways to the thalamus?
Superior and lateral vestibular nuclei send axons to the ventral posterior complex of the thalamus
