Neuronal feedback between brain and inner ear for growth of otoliths in fish Original Research Article

Previous investigations revealed that fish inner ear otolith growth (concerning otolith size and calcium-incorporation) depends on the amplitude and the direction of gravity, suggesting the existence of a (negative) feedback mechanism.In search for the regulating unit, the vestibular nerve was unilaterally transected in neonate swordtail fish (Xiphophorus helleri) which were subsequently incubated in the calcium-tracer alizarin-complexone. Calcium incorporation ceased on the transected head sides, indicating that calcium uptake is neurally regulated.