Research overview: otolith organs and gravity sensing in cats

Within the vestibular system, the otolith organs, the utricle and saccule, sense linear acceleration and the pull of gravity, complementing the rotation-sensing semicircular canals. This overview surveys the role of the feline otolith organs in detecting head tilt and straight-line movement, information essential for balance and for orienting the body relative to gravity. Tiny mineral crystals in these organs shift with acceleration, bending sensory hairs to generate signals. The survey relates otolith function to the righting reflex and to the maintenance of posture and orientation. It discusses how otolith and canal signals combine to give a complete sense of head motion and position. Understanding the otolith organs rounds out the picture of the feline vestibular system, showing that cats sense not only rotation but also gravity and linear motion. It connects the inner-ear gravity sensors to the cat's ability to know which way is down, a prerequisite for righting and balance.