What is the flow of information in the vestibulo-ocular reflex (VOR) and its functional significance?

• A. Ocular motor nuclei send signals to the semicircular canals to stabilize gaze.
• B. The semicircular canal signals feed into vestibular nuclei, which project to ocular motor nuclei to stabilize gaze during head movements.
• C. The VOR relies on cortical vision only.
• D. The pathway travels from the optic nerve directly to the ocular muscles.

Answer: (B)

The vestibulo-ocular reflex stabilizes vision during head movements by producing eye movements opposite to the head motion, keeping images steady on the retina. The semicircular canals detect angular head velocity and send signals via the vestibular nerve to the vestibular nuclei in the brainstem. From there, the information is projected to the ocular motor nuclei that control the eye muscles, coordinating conjugate eye movements through pathways that connect the ocular nuclei to the appropriate extraocular muscles. The medial longitudinal fasciculus helps synchronize horizontal and vertical tracking so the eyes move in a coordinated way as the head turns.

This pathway explains why the flow from the semicircular canals to the vestibular nuclei and then to the ocular motor nuclei is essential for stabilizing gaze during movement. It’s a fast, subcortical reflex, not driven primarily by cortical vision, and it’s not carried directly from the optic nerve to the eye muscles.