Vestibular (labyrinthine) reflexes

Sensory input from otolith organs and semicircular ducts are used to stabilize the orientation of the head in space. Any rotation or tilting of the head and body as a unit activates motor neurons to muscles which maintain the head vertical with respect to gravity. These (mostly tonic) reflexes have a latency of around 40–200 ms. Those that activate motor neurons to neck muscles are known as vestibulocollic reflexes, those to limb muscle motor neurons are vestibulospinal reflexes. The vestibulocollic reflexes act on the neck muscles to hold the head upright. When the body sways forward the neck extensors contract bringing the head up. When the body sways backwards, then neck flexors are activated. The vestibulospinal reflexes act on limb muscles. They trigger narrowing of arm extensor muscles and leg flexor muscles whenever falling, to decrease the impact of landing. Swaying sideways triggers the extension of ipsilateral limbs to brace alongside further tilt in that direction and in contralateral flexion.