NOT true regarding the vestibulo-ocular reflex (VOR)?

• A. It is stimulated by the movement of endolymph within the semicircular canals
• B. It stabilizes images during head movements
• C. It requires a visual stimulus
• D. VOR typically only compensates for up to 30 second periods at a time

Answer: (C)

The vestibulo-ocular reflex is a vestibular-driven mechanism that keeps your gaze steady during head movement by producing eye movements in the opposite direction of where you’re moving your head. When your head turns, the endolymph in the semicircular canals moves, bending the hair cells and sending signals to eye muscles to generate a counter-rotation of the eyes. This reflex works even without any visual input, so it can stabilize images in the dark. Vision can enhance the overall stability, but the VOR itself does not require a visual stimulus to function. That’s why the statement saying it requires a visual stimulus isn’t true. The VOR does stabilize images during head movements, which is accurate. And there isn’t a strict 30-second limit to its compensation—the reflex continues as long as head movement occurs (though performance can be affected by fatigue or pathology).