Question

What is the vestibulo-ocular reflex (VOR) and what is its adaptive significance?

Answer 1

Fibers from superior, medial and inferior vestibular nuclei descend downwards for short distance along with vestibulospinal tract. Afterwards, these fibers ascend through the medial longitudinal fasciculus and terminate in the nuclei of III, IV and VI cranial nerves, thus forming vestibulo-ocular tract. This tract is concerned with movements of eyeballs in relation to the position of the head.Thus, the vestibular apparatus is responsible for detecting the position of head during different movements. It also causes reflex adjustments in the position of eyeball.

Nystagmus is a reflex phenomenon that occurs in order to maintain the visual fixation. Since the movements of eyeballs occur in response to stimulation of vestibular apparatus this reflex is called vestibulo-ocular reflex.